Stonewall2023 Posted September 24, 2024 Report Share Posted September 24, 2024 Hi All! I currently own an AC-556 & a BRP Stemple -> I am looking to add an 'M16' to my collection within the next few months. I am certainly not an expert and I am looking for some advice on things to look for when trying to purchase a registered 'M16'. I intend to use this firearm as a 'shooter' and was wondering if it is better to get an AR-15 that was converted to an M16? Is there a different set of 'criteria' to look for when inspecting a converted AR-15? Is there anything that would stop a Tranferable M16 from using 'modern' AR-15 uppers? Again, I am not an expert. I appreciate any and all advice! Thank you! Quote Link to comment Share on other sites More sharing options...
jbntex Posted September 24, 2024 Report Share Posted September 24, 2024 (edited) There is a lot to unpack in your question as there are tons of pros, cons, and tradeoff's regarding registered receiver M16s. I would put transferable M16s into a couple class of categories. ------------------------------------------------------------------------------------------------------------------------------------------------------------- At the lower end of the M16 range are the more undesirable host gun conversion or remanufactured gun. These guns would generally include "rewelds" of any type, really old barstock machined SGW or Palmetto lowers, Essential Arms cast lowers, married DIAS sear guns. These guns can have significant dimensional issue, lifespan wear issues, auto sear conversion issues, and/or cosmetic issues. Personally saving a few grand to get one of these M16s IMHO just honestly isn't worth the couple grand in cost savings. ------------------------------------------------------------------------------------------------------------------------------------------------------------- Next up would be the standard group of AR15 conversion guns. These are the AR15 to M16 conversions that generally consist of conversions of forged Sendras, forged SGW/Olympic Arms (and their direct rebranded guns like Frankford, SAW, or PAWS), Colt SP1, and Colt AR15 "Sporter". The non-Colt guns (Sendra and SGW/Olympic) can have some dimensional issue with tight upper to lower fitment issues, tight magwells where poly mags may not fit, and/or cosmetic issue with poor, purple, or no anodizing (just paint). There used to be a small cottage industry of gunsmiths who could "blueprint" these non-Colt lowers so they fit all uppers and mags and then properly type III hardcoat anodize the lowers after being dimensionally corrected but those M16 gunsmith correction services are much more elusive to find today. The non-Colt and Colt conversions can also have not so great auto sear axle pin and sear pocket machining depending upon the skill of the maker doing the conversion. The Colt SP1 and Sporter conversions also come with the non-standard "large" front take down pin arrangement and are cosmetically "slab side" with no mag release "fence". The fence issue is both cosmetic and mechanical (with no ability to add a front takedown pin detent) The large front takedown pin arrangement requires the use of a proprietary non-captured offset front takedown pin to run almost all mil-spec upper made today. Even with an conversion offset pin it can sometimes be hit or miss regarding upper to lower fitment. Some of these large pin Colt conversion lowers have also had bushings installed by gunsmiths in the front takedown ears so an large offset pin doesn't have to be used but you still need a standard takedown pin with some sort of retention mechanism (screw, pin, clip, etc.) as there is no fence with a detent, so the front takedown pin doesn't fall out of the lower when firing. In this category there are some dogs, some really good value shooters , and everything in between. Its a bit of a buyer beware category though as you really need to understand what you are getting. ------------------------------------------------------------------------------------------------------------------------------------------------------------- The next category would be the Colt factory M16s. These would be primarily the Colt factory full auto AR15 models (603, 613, 604, 614), M16, and M16A1 lowers. These won't have any fitment issues, will all be of high quality, etc. The only real significant downside is cost (~$10K premium over a conversion). The other issue is that the anodizing is going to be the old gray type so most modern black uppers won't match the color of the lower resulting in a "two tone" M16. Some folks care, some folks don't, some folks will hunt for matching old gray anodized uppers. ------------------------------------------------------------------------------------------------------------------------------------------------------------- The last category is what I would call the collector guns. These are M16s that offer little in terms of functional/mechanical difference over a regular Colt M16 but are higher priced. These would be the true forging correct Colt M16A2s, the reman Keosayian collection M4s, C&R 601 guns, H&R guns, rare models, cutaways, protos, etc. I would probably put the Group Industry solid stainless steel lowers in this group as well given their rarity and high cost (although it could be argued they are mechanically better being close to indestructible) ------------------------------------------------------------------------------------------------------------------------------------------------------------- Personally I own two forged SGW/Olympic Arms M16 lowers that were both blueprinted by M60Joe and then Type III anodized modern M4 black by US Anodizing. Zero fitment issues, mag release fence, standard front takedown pin with detent, modern black to match uppers today, and saved a significant amount of money over a pair Colt M16s. Only downside to me personally is no Colt Rampant Horse logo on the side. I have had one lower for almost 25 year and the other for probably a dozen years and both have provided decades of reliable shooting. What works best for you is really what attributes you want and how much you want to spend (or save). Hopefully this gets you started and good luck with whatever you decide. Edited September 25, 2024 by jbntex 4 6 Quote Link to comment Share on other sites More sharing options...
Chef Posted September 25, 2024 Report Share Posted September 25, 2024 Everything jbntex said is spot on. The only thing I could add is that factory Colt M16s (in which ever flavor) will appreciate in value better and sell quicker than conversions, rewelds or clones. And considering the amount of money you are spending for any transferable M16 style of firearm, it only makes sense to do whatever you have to do to get the best you can from the start. When you're holding your newly purchased, rough finished Sendra and going through your mag stash to weed out the ones that don't fit well, you'll be wishing you spent the extra money for a factory Colt. For some people there is "pride of ownership". If you feel just as comfortable wearing a fake Rolex as you would wearing a real one, then you probably won't care much if you've got a "factory" M16 or just one that "works". But if wearing that knockoff Rolex would bother you, then there''s a good chance that you'll regret not going all-in and buying the best from the get-go. Quote Link to comment Share on other sites More sharing options...
johnsonlmg41 Posted September 25, 2024 Report Share Posted September 25, 2024 Oh no, I'm totally confused I bought a fake rolex and with the savings bought a colt M16 (back in the day when the M16's were 5K, same as a rolex). After that I bought a Sendra......then with the savings on that, got a couple shrike uppers for it. I admit I only wore the rolek a couple times, but I shoot the Sendra more than the colts. Not sure what that does to my psychological profile? Get what you can get and what suits your needs, every option is a better option than not having any? They are all pretty adaptable to however you want to configure them. They all shoot the same and from 10 feet you can't tell a colt from a Sendra. Quote Link to comment Share on other sites More sharing options...
jbntex Posted September 25, 2024 Report Share Posted September 25, 2024 (edited) I have two real Rolexes and two non-Colt M16s so not sure what that says about my buying/collection habits. Then again I am also a pretty big supporter of the red-headed-bastard-step-child of the transferable M16 world.... the SWD Registered Lightning Link. I own three Lightning Links and shoot the RLLs more than either of the two registered receiver M16s. I have also turned a couple local friends to the RLL dark side as well. I will say that there very well can be a pride of ownership aspect for some folks and if your heart really want a real deal OEM factory Colt M16, there is only one way to get that experience and its buying an OEM Colt M16. However, I am not sure if I would 100% align with the thought that your standard Colt M16 will materially appreciate in value better than a decent conversion M16. I bought my first SGW/Oly back around 2000ish and paid $3500 for it. A Colt would have cost me about $5000ish. Fast forward ~24 years and they both have appreciated about 8% per year to ~$27,000 for the Conversion M16 and ~$37,000 for the Colt M16. While there are some issues with machinegun price guide....however if you compare the trend of Conversions vs. OEM M16s you will see the same movement in pricing over the years and almost the same value increase in terms of "percentage" from ~2004 when the data starts to 2024. In ~2004 conversions started at ~$8K and Colts ~$12K and both have increased on average about 6% to 7% per year since then ending up in the upper $20K for conversions to upper $30K for OEM Colt M16s today. I would argue if capital appreciation is your motive in any way, buy the best priced/ decent condition conversion M16 you can and put the balance you save in a real investment (like a S&P mutual fund) that will most likely appreciate more over time, have better tax treatment, and also not have the value depreciation risk due to damage, loss, or legislation. In terms of sales velocity, I don't have enough M16 selling experience to say whether well done conversion M16 vs. Colt OEM M16 sell faster. While there are clearly slow and hot markets for M16s as represented in the charts above. In general over the years what I have noticed is that it seems like speed of sale is more a factor of a gun being priced fairly/accurately and if the gun is dealer sold and F3 transfer eligible vs. just a Conversion vs. OEM Colt M16 aspect. Just my two cents anyway. Edited September 25, 2024 by jbntex 1 Quote Link to comment Share on other sites More sharing options...
Lzxray Posted September 25, 2024 Report Share Posted September 25, 2024 JBNTEX, always appreciate your well reason write ups. While OP was asking about R.R., it's worth mentioning that a drop in auto sear (DIAS), especially all steel models from JCB, SWD and others, appreciated the most, tracking in the range of an H.K. sear. It was selling for less than a Colt 16 at one time, but gone up quickly once the Shrike came on the scene. With a beltfeed upper such as an FM-9 with its blow back design, the RLL Link (in a KNS Link Protector) is a good fit. Quote Link to comment Share on other sites More sharing options...
Stonewall2023 Posted September 25, 2024 Author Report Share Posted September 25, 2024 From reading all of the comments I think I am going to lean towards an OEM M16 for the simplicity of fittment issues being mitigated. I have read about DIAS and lightning links, what is the benefit of these as opposed to an M16 lower? Do these fit in more host guns outside of the Ar-15 family? Once upon a time I thought I read that RLL only fit on SP1s, is this true? Or do they fit on modern AR-15 lowers? Thanks for all the advice so far guys! Thanks! -Stonewall Quote Link to comment Share on other sites More sharing options...
hkg3k Posted September 25, 2024 Report Share Posted September 25, 2024 5 hours ago, Stonewall2023 said: From reading all of the comments I think I am going to lean towards an OEM M16 for the simplicity of fittment issues being mitigated. I have read about DIAS and lightning links, what is the benefit of these as opposed to an M16 lower? Do these fit in more host guns outside of the Ar-15 family? Once upon a time I thought I read that RLL only fit on SP1s, is this true? Or do they fit on modern AR-15 lowers? Thanks for all the advice so far guys! Thanks! -Stonewall My wife has all the Rolex's (real) in the family...and I'm not saying how many she has In a nutshell, a RDIAS replaces the factory auto sear and is both portable / renders the lower receiver a "cheap throwaway part" rather than a $$$ registered lower that you don't want to get beat up or damaged. If it matters (and to some it does), only a small percentage of the transferable lowers out there are A2 spec with the reinforcements that came with that upgrade...and those A2 guns go for a big to huge premium, depending. The vast majority of transferable "M16s" are A1 spec. With a RDIAS, you can drop it into any modern, compatible, A2+ spec (or specialty) lower receiver, with M16 fire control parts and (without any modifications) run a conventional upper, 9mm, .22, belt-fed, etc. just as you would with a conventional registered lower. It simply adds another layer of versatility to the "most versatile platform" and makes the lower receiver the "cheap" part. If you're familiar with the HK platform and how registered HK sears add portability / versatility to that platform...the same analogy applies to the M16 with a RDIAS. The downside for a RDIAS is the cost and finding one. If you do decide to go in that direction, I'd second the above advice and buy one made from steel, from a known maker. Good luck with your decision. Quote Link to comment Share on other sites More sharing options...
jbntex Posted September 26, 2024 Report Share Posted September 26, 2024 (edited) There are pros/cons for Registered Receiver M16 vs. Registered M16 conversion devices (Drop in Auto Sear and Lightning Links) Owning both types (RR and RLLs) and having friends with RDIASs, the biggest benefit to the registered receiver M16 is simplicity. There is basically nothing you have to do to get an M16 Registered Receiver lower to run from a lower fire control group perspective (discounting upper receiver gas issues or lower buffer issues). Slap any good upper on a RR lower with the proper buffer installed and it will run. The internal fire control components are 100% factory M16 full auto parts and are also fixed in orientation via their pin hole locations. Its virtually almost impossible to fuck up the fire control group function of a Registered Receiver M16 from a lower fire control group perspective unless something is worn or broken. If you want something that is reliable out of the box, are not mechanically inclined, and have no real interest in becoming mechanically inclined and/or knowledgeable on the platform than a Registered Receiver M16 is your horse. The downside to a Registered Receiver is that it is susceptible to damage. If you damage the lower with an over/under-charged round, a 300BLK finds its way into a 5.56 chamber, the gun falls out of your Polaris hunting, you break off one of the trigger guard ears or LRBHO buttress trying to change the parts out, the hammer pin holes get egged out or the LRBHO pocket gets dented shooting 9mm, etc. the damage is to the registered part and fixing damaged aluminum M16 receivers is really difficult. With a Registered Receiver M16 you are also also limited to standard AR15/M16 uppers and the calibers they support. Some of the more unique uppers (like the Shrike/MCR) require changing out lower receiver parts like the LRBHO lever as well. --------------------------------------------------------------------------------------------------------------- The Registered Drop in Auto Sear (RDIAS) has some unique advantages over the registered receiver M16 as well as some limitation. The biggest benefit to the RDIAS is basically all of the receiver based wear/tear/damage issues go away. Out of battery kaboom, buy a new $100 lower, egg out the pin holes buy a new $100 lower, crack the buffer tube retaining ring buy a new $100 lower. You want a non-standard lower setup specifically for unique upper/caliber use cases this is where the RDIAS shines as well. - Shrike/MCR that is a "SAW Box" cut . - Dedicated 9MM lower that takes Glock mags .. - 7.62x39 AR15 lower that takes AK mags. - 7.62x51 in a Colt 901. - Unique 5.56 lower like an HK416. The other major benefit is that RDIAS almost exactly replicates the function of the factory M16 auto sear. So with exception of the RDIAS itself the rest of the parts (trigger, disco, selector, bolt carrier) are all 100% factory M16 parts. This does simplify setup, repairs, spare parts, etc. As for the downsides to the RDIAS.... - They can have timing and/or trip issues. I have had a couple sick RDIAS based guns come to me for help over the years due to poor fitment of the RDIAS to the host resulting in bad timing and/or poorly shaped/worn trips. For the 100% plug and play owners that are in the "I don't even know how to clean my own guns" crowd RDIAS setup and timing issues can present a bit of a challenge. - RDIASs are small and its easier to lose them vs a full sized receiver. They are also not necessarily "retained" in the lower so it possible for them to fall out of the lower when you take the upper off, which can be a butt pucker moment if it falls out in the grass and dirt at the range. Although some are retained to the lower via friction or set screws. - When moving from host to host you legally shouldn't be leaving a full set of M16 fire control groups in your AR15 host guns as they can/will "slam fire" in full auto when set to the Auto position without the RDIAS installed. So technically you should be removing and moving the M16 fire control group parts with the RDIAS which makes moving the RDIAS from host to host at the range a bit more challenging. Some folks don't care and just leave full M16 FCGs in all their AR15 host guns, some just remove/move the full auto selector or hammer, other just set up one lower and RDIAS and never move anything and just switch uppers. - Cost is another factor as RDIAS are currently running $50K or more so a significant cost premium to even a OEM Colt M16A1. --------------------------------------------------------------------------------------------------------------- Similar to the RDIAS, the Registered Lighting Link (RLL) also removes all of the potential receiver based wear and damage concerns of the Registered Receiver M16. Also similar to the RDIAS the RLL also opens the door to a bunch of different host lowers and calibers and more. In an attempt to not turn this into a "what is legal" discuss I am going to refrain from discussing what other unique hosts a RLL can fit into and function that a RDIAS cannot but search on the for sale board and you can see some of the other unique hosts where gunsmith services are offered to do RLL host gun setup where a RDIAS won't work. The RLL also doesn't leave a host AR15 lower with full auto parts that can result in auto slam fire auto mode with the RLL removed. As a result it easier and quicker to move the RLL from RLL prepped host to RLL prepped host at the range. Another advantages of a RLL over the RDIAS is that the link is generally retained in the lower by the hammer so if you take the upper off the RLL won't generally fall out like a RDIAS can. The final advantage is price being less than half the cost of a RDIAS and in general even less expensive than even a conversion M16 lower (although pricing recently seems to have gone up significantly) So you can get toughly two RLLs for one RDIAS. As for RLL downsides....they are numerous but if you put in the time and effort almost all of them can be overcome. - The RLLs are not as robust in construction as either a Registered Receiver or a RDIAS and if set up incorrectly and/or abused can break. Now usually it just the ears on the back that can break and they are repairable but its still a kick in the nuts if you break a $20K RLL. However in my experience if you set them up properly, use a good protector (I have mixed feelings on the KNS units), and don't abuse them they appear to be in my experience almost immune from damage. - Getting a RLL working with a 22LR kit is devilishly complex in comparison to a RR or RDIAS. - RLL require a lot of proper setup to not only run properly but to also not damage them. - You will need to get very proficient with the RLL unique installing an upper process as you can't just pull the rear pin and swing the upper open and back closed on the front pin anymore like you can with a standard AR15 or M16. Reinstalling an upper is always a remove both pins and slide the upper on a unique way proposition. After a while it comes second nature though. - Natively the RLL was designed to work with standard semi-auto AR15 fire control components that resulted in a Safe and Full Auto only firing mode. To get Safe-Semi-Auto with a Lightning Link it requires "custom" modified burst fire control parts. - The RLL was was designed to work with the old style "SP1" semi auto rear profiled carrier which is pretty much a rarity now-a-days so you will be milling most bolt carriers to function. 9mm bolts require a pretty large channel to be milled which honestly kinda sucks to do. Some uppers (like the FM9) also require welding as well as they are missing critical material. So in summary to properly set up a RLL host you need to mill the lowers rear pocket for proper clearance so the RLL can move freely and doesn't bind up. In most cases mill the bolt carrier groups to old school semi spec, you need a RLL protector of some sort to take the strain off of and protect the ears, you may need to modify the bottom of the upper rear lug for clearance, and you will need custom fire control parts for Safe-Semi-Auto operation. Personally I also run a reduced power disco spring(s) as well. If you are not mechanically inclined, don't own a vertical mill (or know somebody who owns a vertical mill), and are not interested in all the knowledge and steps to properly set up a RLL host for timing, function, and to prevent damaged then RLLs are IMHO really not a good option for the not really committed owners as you will be sending every host lower and/or upper off for gunsmith modification or damaging the link if you do it yourself and don't do it right. However, if you have access to a mill and are mechanically inclined, the RLL can be a really neat and unique M16 conversion device option. Again hope this helps. Edited September 26, 2024 by jbntex 4 2 Quote Link to comment Share on other sites More sharing options...
pinball-1 Posted September 26, 2024 Report Share Posted September 26, 2024 18 minutes ago, jbntex said: There are pros/cons for Registered Receiver M16 vs. Registered M16 conversion devices (Drop in Auto Sear and Lightning Links) Owning both types (RR and RLLs) and having friends with RDIASs, the biggest benefit to the registered receiver M16 is simplicity. There is basically nothing you have to do to get an M16 Registered Receiver lower to run from a lower fire control group perspective (discounting upper receiver gas issues or lower buffer issues). Slap an good upper on a RR lower with the proper buffer installed and it will run. The internal fire control components are 100% factory M16 full auto parts and are also fixed in orientation via their pin hole locations. Its virtually almost impossible to fuck up the fire control group function of a Registered Receiver M16 from a lower fire control group perspective unless something is worn or broken. If you want something that is reliable out of the box, are not mechanically inclined, and have no real interest in becoming mechanically inclined and/or knowledgeable on the platform than a Registered Receive M16 is your horse. The downside to a Registered Receiver is that it is susceptible to damage. If you damage the lower with an over/under-charged round, a 300BLK finds its way into a 5.56 chamber, the gun falls out of your Polaris hunting, you break off one of the trigger guard ears or LRBHO buttress trying to change the parts out, the hammer pin holes get egged out or the LRBHO pocket gets dented shooting 9mm, etc. the damage is to the registered part and fixing damaged aluminum M16 receivers is really difficult. With a Registered Receiver M16 you are also also limited to standard AR15/M16 uppers and the calibers they support. Some of the more unique uppers (like the Shrike/MCR) require changing out lower receiver parts like the LRBHO lever as well. --------------------------------------------------------------------------------------------------------------- The Registered Drop in Auto Sear (RDIAS) has some unique advantages over the registered receiver M16 as well as some limitation. The biggest benefit to the RDIAS is basically all of the receiver based wear/tear/damage issues go away. Out of battery kaboom, buy a new $100 lower, egg out the pin holes buy a new $100 lower, crack the buffer tube retaining ring buy a new $100 lower. You want a non-standard lower setup specifically for unique upper/caliber use cases this is where the RDIAS shines as well. - Shrike/MCR that is a "SAW Box" cut . - Dedicated 9MM lower that takes Glock mags .. - 7.62x39 AR15 lower that takes AK mags. - 7.62x51 in a Colt 901. - Unique 5.56 lower like an HK416. The other major benefit is that RDIAS almost exactly replicates the function of the factory M16 auto sear. So with exception of the RDIAS itself the rest of the parts (trigger, disco, selector, bolt carrier) are all 100% factory M16 parts. This does simplify setup, repairs, spare parts, etc. As for the downsides to the RDIAS.... - They can have timing and/or trip issues. I have had a couple sick RDIAS based guns come to me for help over the years due to poor fitment of the RDIAS to the host resulting in bad timing and/or poorly shaped/worn trips. For the 100% plug and play owners that are in the "I don't even know how to clean my own guns" crowd RDIAS setup and timing issues can present a bit of a challenge. - RDIASs are small and its easier to lose them vs a full sized receiver. They are also not necessarily "retained" in the lower so it possible for them to fall out of the lower when you take the upper off, which can be a butt pucker moment if it falls out in the grass and dirt at the range. Although some are retained to the lower via friction or set screws. - When moving from host to host you legally shouldn't be leaving a full set of M16 fire control groups in your AR15 host guns as they can/will "slam fire" in full auto when set to the Auto position without the RDIAS installed. So technically you should be removing and moving the M16 fire control group parts with the RDIAS which makes moving the RDIAS from host to host at the range a bit more challenging. Some folks don't care and just leave full M16 FCGs in all their AR15 host guns, some just remove/move the full auto selector or hammer, other just set up one lower and RDIAS and never move anything and just switch uppers. - Cost is another factor as RDIAS are currently running $50K or more so a significant cost premium to even a OEM Colt M16A1. --------------------------------------------------------------------------------------------------------------- Similar to the RDIAS, the Registered Lighting Link (RLL) also removes all of the potential receiver based wear and damage concerns of the Registered Receiver M16. Also similar to the RDIAS the RLL also opens the door to a bunch of different host lowers and calibers and more. In an attempt to not turn this into a "what is legal" discuss I am going to refrain from discussing what other unique hosts a RLL can fit into and function that a RDIAS cannot but search on the for sale board and you can see some of the other unique hosts where gunsmith services are offered to do RLL host gun setup where a RDIAS won't work. The RLL also doesn't leave a host AR15 lower with full auto parts that can result in auto slam fire auto mode with the RLL removed. As a result it easier and quicker to move the RLL from RLL prepped host to RLL prepped host at the range. Another advantages of a RLL over the RDIAS is that the link is generally retained in the lower by the hammer so if you take the upper off the RLL won't generally fall out like a RDIAS can. The final advantage is price being less than half the cost of a RDIAS and in general even less expensive than even a conversion M16 lower (although pricing recently seems to have gone up significantly) So you can get toughly two RLL for one RDIAS. As for RLL downsides....they are numerous but if you put in the time and effort almost all of them can be overcome. - The RLLs are not as robust in construction as either a Registered Receiver or a RDIAS and if set up incorrectly and/or abused can break. Now usually it just the ears on the back that can break and they are repairable but its still a kick in the nuts if you break a $20K RLL. However in my experience if you set them up properly, use a good protector (I have mixed feelings on the KNS units), and don't abuse them they appear to be in my experience almost immune from damage. - Getting a RLL working with a 22LR kit is devilishly complex in comparison to a RR or RDIAS. - RLL require a lot of proper setup to not only run properly but to also not damage them. - You will need to get very proficient with the RLL unique installing an upper process as you can't just pull the rear pin and swing the upper open and back closed on the front pin anymore like you can with a standard AR15 or M16. Reinstalling an upper is always a remove both pins and slide the upper on a unique way proposition. After a while it comes second nature though. - Natively the RLL was designed to work with standard semi-auto AR15 fire control components that resulted in a Safe and Full Auto only firing mode. To get Safe-Semi-Auto with a Lightning Link it requires "custom" modified burst fire control parts. - The RLL was was designed to work with the old style "SP1" semi auto rear profiled carrier which is pretty much a rarity now-a-days so you will be milling most bolt carriers to function. 9mm bolts require a pretty large channel to be milled which honestly kinda sucks to do. Some uppers (like the FM9) also require welding as well as they are missing critical material. So in summary to properly set up a RLL host you need to mill the lowers pocket for proper clearance so the RLL can move freely and doesn't bind up. In most cases mill the bolt carrier groups to OG semi spec, you need a RLL protector of some sort to take the strain off of and protect the ears, you may need to modify the bottom of the upper rear lug for clearance, and you will need custom fire control parts for Safe-Semi-Auto operation. Personally I also run a reduced power disco spring(s) as well. If you are not mechanically inclined, don't own a vertical mill (or know somebody who owns a vertical mill), and are not interested in all the knowledge and steps to properly set up a RLL host for timing, function, and to prevent damaged, RLLs are IMHO really not a good option for the plug and play type owners as you will be sending every host lower and/or upper off for gunsmith modification. However, if you have access to a mill and are mechanically inclined, the RLL can be a really neat and unique M16 conversion device option. Again hope this helps. Awesome write up. I have a few mg's and thought I knew a bit, but never fully knew the ins and outs of a RLL, so this information is appreciated! Quote Link to comment Share on other sites More sharing options...
Stefan1235 Posted September 26, 2024 Report Share Posted September 26, 2024 Lots of great info here, I’m also looking at picking up an M16 and this has been very helpful. Question: is there a difference between SGW and Frankford lowers? One better or more desirable than the other? I’m not a collector, interested in buying a shooter and would rather not wear out a Colt so figured I’d stick with a conversion but not sure which conversion is best? Quote Link to comment Share on other sites More sharing options...
jbntex Posted September 26, 2024 Report Share Posted September 26, 2024 (edited) All of the Olympic / Schuetzen Gun Works (SGW) receivers whether it be their in house "Stop Sign" brand or their contract manufactured "rebranded" (Palmetto, SAW, PAWS, Frankford, etc.) receivers they were all made originally as Title-1 AR15 receivers by Olympic/SGW. At an "apples to apples" comparison there is no difference between an in house SGW/Oly "Stop Sign" branded receiver and say a contract manufactured receiver. (more on that below though) One other aspect on these M16s is that Olympic/SGW themselves didn't make machineguns so essentially every one of these M16s whether it is an in-house SGW "Stop Sign" brand or contract manufactured brand is a conversion of some type/degree. In terms of Oly/SGW receiver quality (in house brand or contract manufactured) there are a few things to keep in mind. Not all Olympic/SGW receivers whether their own in house "Stop Sign" branded receivers or their contract manufactured receivers are of the same "quality". As Oly/SGW progressed over the years they got better and better at making AR15 lowers. So in general the older/earlier the generation of Oly/SGW AR15 lower the more "rough" its going to be and the newer the receiver generally the better/cleaner it is going to be. These receiver "improvement" also crossed over both the in house "Stop Sign" brand receivers and the contract receiver manufacturing as well as time went on. So when I say at a "apples to apples" comparison between a "Stop Sign" Oly/SGW branded lower and a contract manufactured receiver (like a Frankford) that is in terms of the generation of the base AR15 receiver that Oly/SGW made. As example, you can have early gen SGW "Stop Sign" receivers and early gen Frankford receivers and you can have later gen SGW "Stop Sign" receivers and later gen Frankford receivers. If you compare an early Frankford against a late gen Oly/SGW Stop Sign the later gen Oly/SGW Stop Sign is going to be better. Vis-versa a newer Gen Frankford receiver is going be be better when compared against an older gen Oly/SGW. The first gen receivers that Oly/SGW made were not good. They were essentially made out of chuck of soft aluminum bar stock that was crudely milled to shape. The material is not ideal, the dimension leave a lot to be desired, and the receiver aesthetics suck something awful. Over time Oly/SGW moved on to making proper forged based lowers which was a huge improvement. However the early forged lowers, the surface finish isn't as good, there can be little depressions/flashing and machining marks, the selector bosses can be a bit crude, they had little nub or key that stuck out of the exterior receiver wall to prevent a selector from rotating to the full auto position that had to be milled off leaving a varying cosmetic defect depending upon the skill of the person doing the conversion. The factory fire control markings on the older receivers are just "S" and "F" vs. "Safe" and "Fire" and the later gen unit. The last year or so before the 86 cutoff the Oly/SGW seemed to have dialed in the manufacturing better and they cleaned up the minor forging imperfections, eliminated most of the machine/tooling marks, and on some of the receivers the little selector rotation nub appears to have been eliminated, etc. My guess is that this is probably why some original/untouched Oly/SGWs receivers fit standard uppers better than others. Now none of the Oly/SGWs are as clean as a Colt M16 lower but in general they got progressively better as time went. Some of the later gen lowers were also not anodized as its my guess in the rush to get as many lowers out the door to FFL/SOT who wanted them for conversions they went out in the raw. Many of these were just painted after conversion and I have seen converted but still raw Oly/SGWs for sale in years past. The second Oly/SGW I bought was like this, an 86 era serial #, conversion by an FFL/SOT, but no anodizing and just spray painted. So in general the later the gen receivers are generally better regardless of the branding with a big quality shift being when they moved from milled to forged lowers and then incremental improvements to the forged lowers as time progressed. So say a Frankford forged sn# FA1400 is going to be nicer/cleaner than an FA0400 which in turn is going to be much better than a milled barstock FA0004. The same goes for Oly/SGW "Stop Sign"s or PAWS. The other aspect on these guns is whether or not the lowers were random conversions of Oly/SGW Stop Sign receiver or whether it was specifically contract manufactured for 3rd party with the intension of becoming a machinegun. This is where contract manufacturer who specialized in M16 conversions like Frankford and Police Automatic Weapons Service (PAWS) guns conversion quality comes into play as the conversion work was of a known quantity vs. some random guy on a Form 1 and a drill press. Some of these contract manufactured receivers the rear pocket appear to be relieved by Oly/SGW for an Auto Sear so that pocket area is all finished on the interior of the receiver and the M16 conversion work was to just drill the auto sear pin hole. That is not to say that there are not good individual made or random 07/02 type conversion but the rebrands like PAWS or Frankford are generally more of a known quantity in terms of the actual conversion work. There is one last type of Oly/SGW to bring up and that is the remans. In the mid 2000s Oly had a program where you could send them a transferable M16, they would destroy the lower and replace it with the same serial number. From a mechanical/quality perspective these are probably the best Oly/SGW lowers out there. However they have a dark cloud of legal pedigree questions that hang over them as it really wasn't "legal" for Oly to do this. While its a bit questionably for an OEM to replace their own transferable machineguns (like Colt has done in the past with factory M16s) but Oly technically wasn't even the original maker of the "machinegun" which makes it twice as sketchy. When I personally pressed Tom Spithaler on this at the time (as I was considering sending in my gun) he provided me a letter about the legality of replacing a 1994 AWB "pre-ban" semi-auto AR15 and the replacement retaining pre-ban status, which was irrelevant to machinegun replacement, so I declined. At the end of the days the remans are easy to spot as they are all modern M4 style forgings (vs A1) and the markings are much thicker line weight and CNC done vs. the light pantograph style lines on the originals. The mid 2000s remans are across both the in-house and contract manufactured receivers as well. Its up to the buyer if they want to take the legal risk on one of these guns. Here are some pics of the different gens of Oly/SGW made Frankfords. The top is a early serial milled barstock receiver. The middle is a 100's range serial where its now forged (huge improvement) but you can see little depressions/flashing imperfections in the forging, tooling marks, etc. The bottom receiver is a 1000 serial range where the forging is a bit cleaner/smoother and machining operations (like the selector stops) are just better executed. Hope this helps. Edited September 27, 2024 by jbntex 2 1 Quote Link to comment Share on other sites More sharing options...
AZFNFAL Posted September 28, 2024 Report Share Posted September 28, 2024 Wow , I only paid $1800 for my Colt M16 A1 Carbine in 1986. I remember I stopped at another gun shop when going to a different gun shop to buy my wife's first Colt AR15 . The guy there opened a safe that had about a dozen Colt M16's and said I could buy one for $700 plus transfer. I told him he was nuts , I was headed over to the other shop and bought her first for $375.00. Still have it. THAT was the Good Old Days ! Quote Link to comment Share on other sites More sharing options...
rhouston8 Posted October 3, 2024 Report Share Posted October 3, 2024 My 2 cents as a Reg Rec SP1 conversion owner and a RLL x 2 owner. I'm a "shooter" not a collector. Converted SP1 fits the bill perfectly for me and sounds like it would for you. It has a large front pin hole- so what?- Just add one of those special large->small pin conversion things. Good to go. No fitment or tinkering with SP1 really. I run a Shrike on mine. No problems. The RDIAS is much too $$$ for me. The RLL is good to use to beat up on other hosts- but it does take some tinkering unlike the SP1. Buy a cheaper converted AR15 and pocket the difference from say a M16a1. 1 Quote Link to comment Share on other sites More sharing options...
Don. Posted October 11, 2024 Report Share Posted October 11, 2024 On 10/3/2024 at 9:19 AM, rhouston8 said: My 2 cents as a Reg Rec SP1 conversion owner and a RLL x 2 owner. I'm a "shooter" not a collector. Converted SP1 fits the bill perfectly for me and sounds like it would for you. It has a large front pin hole- so what?- Just add one of those special large->small pin conversion things. Good to go. No fitment or tinkering with SP1 really. I run a Shrike on mine. No problems. The RDIAS is much too $$$ for me. The RLL is good to use to beat up on other hosts- but it does take some tinkering unlike the SP1. Buy a cheaper converted AR15 and pocket the difference from say a M16a1. I’m in the same boat. Instead of adapter pins, I bought several used, stripped SP1 uppers and assembled them to my desired configurations, to include a dedicated .22 upper. Keeping the large pin in the front keeps it simple for me. I did have to get the relief cut made in the uppers for the sear, but I have a guy that does it right and cheap that’s local to me. This is a shooter and it’s been 100% for all uppers after the initial tuning of each. Quote Link to comment Share on other sites More sharing options...
MP5 Posted February 5 Report Share Posted February 5 On 9/24/2024 at 11:13 AM, Stonewall2023 said: Hi All! I currently own an AC-556 & a BRP Stemple -> I am looking to add an 'M16' to my collection within the next few months. So ....... what did you end up getting? Enquiring Mimes want to know! Quote Link to comment Share on other sites More sharing options...
Got Uzi Posted February 6 Report Share Posted February 6 I had a Colt SP1 conversion M16 back in the day (sadly sold it) but I personally liked having the large front pin as there could never be a confusion with what uppers went to what. There wasn’t anything that could be said for “constructive intent” with having short uppers that could go onto a standard AR lower. Its not that hard to make standard uppers into large pin uppers (endmill and Bridgeport milling machine for the win) My M16 lived as a 9mm DOE gun most the time, and if it wasn’t being shot as an SMG, it had a 22LR upper on it. Rarely did I shoot 223/556 out of it. I will say this, even though I have an HK sear, I’m considering an M16 again as it’s a cheaper setup to have an M16 lower with a Shrike upper vs an HK sear and HK23E host….just food for thought. Quote Link to comment Share on other sites More sharing options...
johnsonlmg41 Posted February 6 Report Share Posted February 6 44 minutes ago, Got Uzi said: Its not that hard to make standard uppers into large pin uppers (endmill and Bridgeport milling machine for the win) My M16 lived as a 9mm DOE gun most the time, and if it wasn’t being shot as an SMG, it had a 22LR upper on it. Rarely did I shoot 223/556 out of it. I will say this, even though I have an HK sear, I’m considering an M16 again as it’s a cheaper setup to have an M16 lower with a Shrike upper vs an HK sear and HK23E host….just food for thought. I have two bridgeports.....but I bought an offset pin.....way faster than the mill. I felt like a winner, but maybe I'm just lazy? Quote Link to comment Share on other sites More sharing options...
Got Uzi Posted February 6 Report Share Posted February 6 The SP1 I had didn’t like shooting anything Centerfire with an offset pin hence why I did what I did. Quote Link to comment Share on other sites More sharing options...
WI Hunter Posted February 6 Report Share Posted February 6 Another great informative thread. Thanks! Quote Link to comment Share on other sites More sharing options...
thisismyboomstick Posted February 7 Report Share Posted February 7 How did I not see this until now? This has to be the best summary of the ownership considerations for the various M16 options in internet land so far. jbntex is the man! 1 Quote Link to comment Share on other sites More sharing options...
gamebit21 Posted February 7 Report Share Posted February 7 hello to all. Me personally, I love having several of the group industries M16A1 Stainless steel lowers. Sure the are a pound heavier, and they are specked out like the latest and greatest M16A2s. They even could be marked M16A1 and 2 under license from that time period. Short of the say boarded steel DIAS, they are virtually indestructible. Hanging these combined with a DLO registered HL Teogger Box pretty much covers everything from 22 cal upper ( drum type and belt fed) to a 308 caliber belted and everything in between. The other really nice consideration was not because of an opinion letter in 2015. Those are shaky ground. Supposedly MAC 11 trigger group sear modules could be use in any semi auto gun as long as the host was hot prenatal altered or the receiver. Someone had listed one used to convert a semi only PKM host. And again, opinion letters are just certified toilet paper. Allot of people here know what happened to the XMG 308 caliber M16 belt fed upper…. Around 2008, oh sure it’s cool here is your letter. Then in 2013,, oh NO!! You have made another machinegun!! Anyways great thread I will save it!! Dare I say Gospel info!! Like me you are on the right track. Just have a shooter to ahoot and enjoy!! Investments are other things…. All the best…. Scott Quote Link to comment Share on other sites More sharing options...
Slipkid65 Posted February 8 Report Share Posted February 8 (edited) What an awesome thread! Years ago, I had a Fleming conversion of a Colt AR-15 A2 (large front pin). Back then we didn't have the plethora of AR parts like we do now, so I picked up a couple of large hole Colt uppers and a couple of Bushmaster barrels for it. I built one as a 20" A2 HBAR and the other set up like an XM177 with an 11.5" barrel. I could never get the 11.5 to run with a carbine buffer/tube. It was seriously overgassed, and would hypercycle. It worked OK with the A2 buffer/tube though. I usually ran the 11.5 with a Ciener 22 unit. It kills me to even type that I paid $1200 for the stripped lower from LMO in the mid 90's. I sold it in the late 90's for $4200 complete as an A2 HBAR, thinking I made a killing. Been kicking myself ever since for selling it. I also got to play with a lightning link a few times. My neighbor, who was a class 3, had one, and we ran it in my semi auto Colt A2 HBAR as well as a couple of other ARs. Ran like a (real) swiss watch too! Fast forward to a few months ago.... I picked up an SGW/Oly PAWS "Stop Sign" conversion from a wonderful gentleman on this board, putting me back into the machine gun club. Bonus was that it took 2 days(!) to transfer on an EForm from my local dealer to our trust! I am happy with it. Overall, it works great, but it's definitely not a Colt. Most of my uppers fit and work perfectly on it, but a few don't (2 Aero M4E1s. One of them fits and functions with certain mags, the other misses hitting the rear takedown pin by a few thousandths). There are also some fitment issues with certain mags/uppers. One of my 22 mags won't lock into it even without an upper installed. Even with those issues, I am glad I bought it and I am considering another MG. It's like reliving my youth, and an added bonus is that I get to share it with my son. There's one that will be available locally soon that I am considering. It's an SP1 conversion done by a company called "Frontier Shop" in Riverton WY. I am not familiar with this Class 2, and was wondering how well regarded they are. The gun is in nice shape overall, and I still have a few large hole uppers lying around for it, so I am tempted. Edited February 8 by Slipkid65 Quote Link to comment Share on other sites More sharing options...
mac1 Posted February 8 Report Share Posted February 8 (edited) I have a GM hydra-matic US property marked re-weld and absolutely love the rifle. If you decide to go with a re-weld, the M16 is not a bad option since the upper is the work horse on the rifle. I get a lot of compliments on the rifle and zero malfunctions so far on either semi or auto. I found a complete GM upper including bolt and charging handle many years ago, so fun to have matching upper and lower. It is a re-weld and the only re-weld I own in my collection, but have really enjoyed it. My form 4 has the manufacturer listed as GM so reinforces not to always go by what is on a form 4. On my rifle, you would need to X-ray it to detect the weld. However at the end of the day it is a re-weld, but I really wanted a GM marked M16A1 since I had one issued to me in the Army. Edited February 8 by mac1 1 Quote Link to comment Share on other sites More sharing options...
MPFiveO Posted February 8 Report Share Posted February 8 I contemplated contributing to this thread but jbntex did a very thorough job of covering just about every aspect. So much so that I'd recommend copying and saving it somewhere. You'll only get this kind of information from guys that have been there, done that. Much of the information he provided is only archived in the minds of guys over the age of 50. While there are plenty of books and articles dedicated to covering the AR-15 and M16 from a collectors aspect, there are none that I'm aware of that document the aspect of conversions done by the numerous C2's that existed in the 1980's. Here's my two cents. I own four M16's. Three are factory Colt's and one is an aftermarket receiver. That fourth one was manufactured by Essential Arms in Louisiana. It's a cast receiver and it was converted and registered by SWD in Atlanta, Georgia. I've rebuilt the receiver in numerous configurations over the years. It was a standard A1 style 20 inch rifle when I got it but soon after it became and stayed a carbine. At about 50K rounds it had shot itself pretty loose so I sent it to M60 Joe and he tightened everything back up and refinished it with a black moly resin that matches most modern black uppers. With the carbine buffer tube I can switch stocks to the aluminum XM177, N1, Waffle, LMT and numerous others. I have lots of carbine uppers including an XM177, M4, MK18 and at least a half dozen more. Pairing up the correct stock and upper takes less than a minute. Since it was refurbished it's probably seen another 20K rounds. It's currently using a CMC trigger and KNS anti rotation pins. I will not be able to wear it out in my lifetime. Knowing what I know now about the cast E.A. receiver I would have used anti rotation pins sooner and would never have shot any 9mm through it. The original unramped 9mm bolts are really rough on hammer pins. Otherwise, I would have zero hesitation to buy another one. The three Colt's are an XM16E1, M16A1 and M16A2. My favorite and least favorite is the M16A2 . I absolutely love a 20 inch rifle and the A2 shoots really well. But the sights are overly complicated for an infantry rifle and the three round burst trigger mechanism leaves a lot to be desired as the trigger pull weight varies with each press depending on where the burst cam is set. I've been an armorer for decades and know how to swap trigger groups out, but I leave the burst group in it so that I can show others how it behaves. What is incredibly fun is to rest the A2 on a sandbag and set the rifle to burst and hit a steel plate at 100 yards with two or three rounds. The XM16E1 is all correct and early parts so the barrel is not chrome lined. I've found this particular rifle to be exceptionally accurate and limit the amount of full auto fire from it. The M16A1 is hands down my favorite rifle period. I carried one in basic training in 1989 and all the way up until 9/11 when my unit was called up for service. At that point we were issued refurbished A2's. My A1 is just a common commercial model in the 9 million serial number range. It would be the last one I'd part with. 1 Quote Link to comment Share on other sites More sharing options...
Stonewall2023 Posted February 10 Author Report Share Posted February 10 On 2/5/2025 at 6:53 PM, MP5 said: So ....... what did you end up getting? Enquiring Mimes want to know! Hi All! I bought and now own a COLT MODEL 614 factory M16 rifle. Looking through the serial numbers I believe that the rifle was manufactured in 1965 and the story behind its previous owner is quite amazing. The gun overall is in really great condition! I also liked that the rifle was stamped AR-15 and it has the COLT pony on the receiver . From brief research these were some of the first M16s that were shipped to Vietnam -> cool history! Given mines condition, I am assuming it never made it out of the USA (Good news for me!) I worked with my local FFL to replace the factory Upper receiver + Lower parts kits with after market parts and have the "original" internals of the gun stored in a collectors bin of items. The "Original" parts from the lower receiver were not visibly stamped with the Colt "C" so we kind of assume that the previous owner may have done the same thing and never replaced the internals to the originals. The upper is stamped with the "C" and is certainly the factory upper. I added the KNS pins to the lower receiver and I am using USGI after market parts. I looked into the Geissele M16 trigger but decided against it for the time being. Replaced the buffer tube + added an H2 buffer which currently runs a suppressed DD MK18 upper (10.5"). The gun runs flawlessly on the upper with no issues (as of today :D). I prefer the M16A1 pistol grip so I decided to not replace that part. Stock was replaced with an LWRCI adjustable stock. I am building a Black Hawk Down Gordy Carbine clone upper that I intend to run on the M16A1, I like having options and honestly it seems pretty cool. I have been meaning to ask this board about recommended red dots/optics for full auto rifles. The Trijicon red-dot I am running has such a small field of view that after 4-5 rounds the target can 'disappear'. The information provided from the board has helped me CONSIDERABLY! Thank you to everyone who contributed knowledge about which direction I should go, I absolutely love my M16. Shamelessly, I will probably end up buying another 'M16' which will be a SP1 or one of the other options that were discussed above. I was in the right place at the right time when the 614 came available, hoping for similar luck with one of the other rifles down the line when I am ready. That Fightlite MCR seems like such a fun setup to run on a transferable M16! Thanks again!! 1 Quote Link to comment Share on other sites More sharing options...
MPFiveO Posted February 11 Report Share Posted February 11 On 2/9/2025 at 9:08 PM, Stonewall2023 said: Hi All! I bought and now own a COLT MODEL 614 factory M16 rifle. Looking through the serial numbers I believe that the rifle was manufactured in 1965 and the story behind its previous owner is quite amazing. The gun overall is in really great condition! I also liked that the rifle was stamped AR-15 and it has the COLT pony on the receiver . From brief research these were some of the first M16s that were shipped to Vietnam -> cool history! Given mines condition, I am assuming it never made it out of the USA (Good news for me!) I worked with my local FFL to replace the factory Upper receiver + Lower parts kits with after market parts and have the "original" internals of the gun stored in a collectors bin of items. The "Original" parts from the lower receiver were not visibly stamped with the Colt "C" so we kind of assume that the previous owner may have done the same thing and never replaced the internals to the originals. The upper is stamped with the "C" and is certainly the factory upper. I added the KNS pins to the lower receiver and I am using USGI after market parts. I looked into the Geissele M16 trigger but decided against it for the time being. Replaced the buffer tube + added an H2 buffer which currently runs a suppressed DD MK18 upper (10.5"). The gun runs flawlessly on the upper with no issues (as of today :D). I prefer the M16A1 pistol grip so I decided to not replace that part. Stock was replaced with an LWRCI adjustable stock. I am building a Black Hawk Down Gordy Carbine clone upper that I intend to run on the M16A1, I like having options and honestly it seems pretty cool. I have been meaning to ask this board about recommended red dots/optics for full auto rifles. The Trijicon red-dot I am running has such a small field of view that after 4-5 rounds the target can 'disappear'. The information provided from the board has helped me CONSIDERABLY! Thank you to everyone who contributed knowledge about which direction I should go, I absolutely love my M16. Shamelessly, I will probably end up buying another 'M16' which will be a SP1 or one of the other options that were discussed above. I was in the right place at the right time when the 614 came available, hoping for similar luck with one of the other rifles down the line when I am ready. That Fightlite MCR seems like such a fun setup to run on a transferable M16! Thanks again!! Just curious what range your serial number is in. The Colt M16's that are roll marked AR-15 and Model 614 would have been made in the 70's and 80's. I watched the video you provided and the lower receiver in the video has a full fence which would be correct for a 614 produced during that time frame. One produced around 1965 would have had a partial fence. I'm guilty of calling things out by the wrong name on occasion but the name I call out fits because of the details. I say I have an XM16E1 but it's not marked XM16E1. It is a factory Colt machine gun and has all XM16E1 features but lacks that roll mark. In all likelihood it's a Model 602. Mine is marked AR-15 but it doesn't have a Model number stamped on it. The caliber is marked .223 instead of 5.56mm. The entire word SERIAL is stamped before the serial number which is 015XXX. This serial number range actually is from the 1964-65 timeframe and the easiest way to confirm that is with the features on the lower receiver. It's a partial fence lower with a pinned buffer tube. The bar that retains the front takedown pin has the plus sign on it. The Colt logo has a space between the circle and globe where later models did not. The manufacturer is Colt's Patent Firearms Mfg Co and Later models were marked Colt's Firearms Division. Here's a copy of the serial number ranges that's been posted in several places on the internet. Supposedly it's pretty accurate. Note that it only makes mention of the 604 which is sort of the equivalent of the 614. The list doesn't make mention of certain other models either such as the Model 639. Most of the commercially marked guns produced in the 70's and 80's fall into four serial number ranges, 4, 5, 8 & 9 million. USGI SERIAL NUMBER DATA BASE (serial numbers listed in chronological rather then numerical order): 101-14,484 1959-1963 US Air Force/Project AGILE/SEAL issue Colt's AR-15 Model 601, roll marked ARMALITE. Some sold commercially to police departments, small numbers to foreign militaries such as Malaya, India, Australia, Burma, and Singapore. 20,000-39,999 1963-1964 US Property marked AR-15 Colt's Model 02 issued to US Advisors in Vietnam, and US Air Force. Few hundred commercial/export examples were made that lack US Property markings. 40,000-49,999 1964 US Property marked US Air Force M16 Colt's Model 604. 50,000-199,999 1964-1965 US Property marked US Air Force M16 Colt's Model 604 & US Army XM16E1 Colt's Model 603. 14,500-14,916 1965 Commercial/export CAR-15 series and US Property marked GX series for S.A.W.S. contract (note, CAR-15 refers to a family of Colt's weapons, not just short ones). 15,000-19,999 1965 Commercial/export CAR-15 series. 200,000-202,446 1965 Commercial/export CAR-15 series. 202,447-379,353 1965 US Property marked US Air Force M16 Colt's Model 604, and a few commercial export models. There are also examples of commerical/export marked models using the 20X,XXX serial number range produced in the late 1960's. 400,000 series 1966-1973 or so Only a few rifles/carbines made in this serial number range and known examples are spread out over several years of production. Zero US Property marked rifles have been observed. Highest know example is 418,XXX and dates from the early 1970’s. 500,001-749,999 1966-1967 US Property marked XM16E1 Colt's and M16A1, both Colt Model 603. There are also a small number of US Air Force M16 Colt's Model 604 found in this serial number range. Serial numbers in this range were not run in order. M16A1’s have been observed with serial numbers as low as 604,505, and XM16E1’s have serial numbers as high as 741,12X. 750,000-752,443 1966 Experimental HBAR. 752,444-899,999 1967 US Property marked M16A1. 900,000 through 909,999 1966-1970 US Property marked Govt. Carbines. 910,000-919,999 Unconfirmed, only know of one Colt in this range, it is in US Air Force inventory, and I do not know the model number. 920,000-999,999 No known examples. 1,000,000-1,999,999 1968-1969 US Property marked Colt's M16A1 2,000,000-2,24X,XXX 1968-1971 US Property marked H&R M16A1. 3,000,000-3,469,217 (approximate) 1968-1971 US Property marked Hydramatic M16A1. 9,000,0000 series 1970’s & 1980’s In general these are 1970’s and early 80’s “A1” type 600 series commercial/export marked weapons. There are some exceptions, for example US Property marked Govt. Carbines. AL prefix 1970 Lebanese contract rifles, some 14,000 made. Note on 4,000,000 series Colt’s, there are quite a few commercial/export marked rifles/carbines mixed in. 4,000,001-4,060,000 1970 US Air Force M16 Colt Model 604. 4,060,001-4,221,800 1970 US Property marked M16A1. 4,221,801-4,285,400 1970 US Air Force M16 Colt Model 604. 4,285,401-4,521,000 1970 US Property marked M16A1. 4,521,001-4,521,850 1970 US Air Force M16 Colt Model 604. 4,521,851-4,638, 400 1970 US Property marked M16A1. 4,638,401-4,643,400 1971 Model 613 for Malaysia. 4,643,401-4,701,400 1971 US Property marked M16A1. 4,701,401-4,701,900 1971 Model 613 Commando 4,701,901-4,844,400 1971 US Property marked M16A1. 4,844,401-4,849,400 1972 Model 613 for Taiwan. 4,849,401-4,926,000 1972 US Property marked M16A1. 4,926,001-4,928,000 1972 Model 613 for Philippines. 4,928,000-4,936,400 1972 US Property marked M16A1. 5,000,000-5,4X,XXX (app) 1973-1982 US Property marked M16A1 Colt's Model 603 (not aware of any Air Force M16 Colt Model 604's with serial numbers this high). Also some export/commercial models. 6,000,000-6,590,478 (approximate) 1983-1986 US Property marked M16A2 & US Property marked XM4 prototypes Colt's Model 720. 8,000,000 series 1980’s In general these are 700 series commercial/export marked models of the M16A2. 7,000,000-7,429,766 (approximate) 1988-2003 US Property marked FN M16A2. There are also Balimoy M16A1 lowers restamped A2 in this serial number range. These were used as replacement parts by Anniston. W prefix 1994-current US Property marked Colt's M4/A1 Carbine, Colt's Model 920/921. A prefix 1990’s on 900 series Commercial/export versions of the M4 Carbine. 10,000,000 serial number range 1997- US Property marked Colt's/FN M16A4 1 Quote Link to comment Share on other sites More sharing options...
MPFiveO Posted February 11 Report Share Posted February 11 Here's some additional information that might be helpful to collectors. Small Arms Review did an excellent article series on the Colt M16 models and their evolution. Each model is specifically listed with a list of their features. The Model 614 is listed in Part 2 of this series. There are also some examples of models like mine in the 015XXX range though they had model numbers stamped on them. They also differ in that they are marked 5.56mm where mine is marked .223. The 607 listed in Part 1 is 79 units away from mine and the 608 is only 28 units away from mine. Both have the same partial fence lower however. https://smallarmsreview.com/the-complete-guide-to-colt-m-16-models-part-i/ https://smallarmsreview.com/the-complete-guide-to-colt-m-16-models-part-ii/ https://smallarmsreview.com/the-complete-guide-to-colt-m-16-models-part-iii/ Quote Link to comment Share on other sites More sharing options...
Stonewall2023 Posted February 11 Author Report Share Posted February 11 @MPFiveO The serial number on my M16 is a 6 dig. 2XXXXX and my research from other machine gun boards (with same serial numbers + Date of manufacturing you provided) drop it in the following category. 1965 US Property marked US Air Force M16 Colt's Model 604, and a few commercial export models. There are also examples of commerical/export marked models using the 20XXXX serial number range produced in the late 1960's. The lower receiver is also stamped "SERIAL 20XXXX". The upper receiver that came with the gun does not have a forward assist and has the 3-prong flash hider. Given that the serial number is on the lower end of the 200000s we believe that the manufacturing time frame was probably 1965, but I was provided a range of manufacturing from 1965-1969. This particular model is the "commercial/export" version of the 604. This particular gun (mine at least) came from a VP at Colt, which I thought was a pretty cool piece of back story. Thanks! Quote Link to comment Share on other sites More sharing options...
gamebit21 Posted February 23 Report Share Posted February 23 M16 Rifle M16 is the U.S. military designation for a family of rifles derived from the ArmaLite AR-15 and further developed by Colt. It is an assault rifle which fires NATO standard 5.56 mm ammunition. It has been the primary infantry rifle of the United States military since 1967, is in use by 15 NATO countries, and has been the most produced firearm in its caliber. Overview The M16 is a lightweight, 5.56 mm caliber, air-cooled, gas-operated, magazine-fed rifle, with a rotating bolt, actuated by direct impingement gas operation. It is constructed of steel, aluminum and composite plastics. There have been four principal versions of the M16. The first was M16, followed by the M16A1, which fired a U.S. M193/M196 round that could fire in either semi- or fully-automatic modes. The second was the M16A2, which entered service in the 1980s and fires the Belgian-designed M855/M856 rounds (adopted at that time as the new 5.56 x 45 mm NATO standard round). The M16A2 can fire either semi-automatic or bursts of up to three rounds. Mode of fire is determined by using a selector switch on the side of the weapon. Finally, the M16A4 became standard issue for the United States Marine Corps during Operation Iraqi Freedom, increasingly replacing the earlier M16A2. In the United States Army, a combination of the M16A4 and M4 Carbine continue to replace existing M16A2s. The M16A4 features a handguard with four Picatinny rails for mounting optical sights, laser pointers, night vision, forward handgrips, removable carry handle and flashlights. The M16 is primarily manufactured by Colt and Fabrique Nationale de Herstal, with variants produced by numerous countries around the world. Semi-automatic versions, generally referred to as "AR-15s" (because of Colt's revival of the nomenclature to describe their civilian line), are popular recreational firearms in the United States, with versions manufactured by a handful of larger manufacturers and over a dozen smaller concerns. The M16 was first adopted in 1964 by the United States Air Force (USAF) as the M16. Various modified versions of the M16 design were subsequently fielded under experimental designations, culminating in the M16A1. The M16A1 was simply the M16 with a forward assist as requested by the Army. This weapon remained the primary infantry rifle of the United States military from 1967 until the 1980s, when it was supplemented by the M16A2. The M16A2, in turn, is currently being supplemented by the M16A4, which incorporates the modular flattop receiver unit developed for the M4 Carbine. Previous versions of the weapon are still in stock and used primarily by reserve and national guard units in the United States as well as by the U.S. Air Force. The M16A3 is a fully-automatic variant of the M16A2, issued primarily within the U.S. Navy. History Project SALVO In 1948, the Army organized the civilian Operations Research Office (ORO), mirroring similar operations research organizations in the United Kingdom. One of their first efforts, Project ALCLAD, studied body armor and quickly concluded that they would need to know considerably more about battlefield injuries in order to make reasonable suggestions. Over 3 million battlefield reports from WWII were analyzed and over the next few years they released a series of reports on their findings. Their basic conclusion was that most combat takes place at short ranges. In a highly mobile war combat teams ran into each other largely by surprise, and the team with the higher firepower tended to win. They also found that the chance of being hit in combat was essentially random — that is, accurate "aiming" made little difference because the targets no longer sat still. The number one predictor of casualties was the total number of bullets fired. These conclusions suggested that infantry should be equipped with a fully-automatic rifle of some sort in order to increase the rate of fire. It was also clear, however, that such weapons dramatically increased ammunition use and in order for a rifleman to be able to carry enough ammunition for a firefight they would have to carry something much lighter. Existing rifles were poorly suited to real-world combat for both of these reasons. Although it appeared the new 7.62mm T44 (precursor to the M14) would increase the rate of fire, its heavy 7.62mm NATO cartridge made carrying significant quantities of ammunition a real problem. Moreover the length and weight of the weapon made it unsuitable for short range combat situations often found in jungle and urban combat or mechanized warfare, where a smaller and lighter weapon could be brought to bear much more quickly. These efforts were noticed by Col. René Studler, U.S. Army Ordnance's Chief of Small Arms Research and Development. Col. Studler asked the Aberdeen Proving Ground to submit a report on the smaller caliber weapons. A team led by Donald Hall, director of program development at Aberdeen, reported that a .22 inch (5.59 mm) round would have performance equal to larger rounds in most combat. With the higher rate of fire possible due to lower recoil it was likely such a weapon would inflict more casualties on the enemy. His team members, notably William C. Davis, Jr. and G.A. Gustafson, started development of a series of experimental .224 inch (5.69 mm) rounds. In 1955, their request for further funding was denied. A new study, Project SALVO, was set up to try to find a weapon design suited to real-world combat. Running between 1953 and 1957 in two phases, SALVO eventually suggested that a weapon firing four rounds into a 20 inch (0.5 m) area would have double the hit probability of existing semi-automatic weapons. In the second phase, SALVO II, several experimental weapons concepts were tested. Irwin Barr of AAI Corporation introduced a series of flechette weapons, starting with a shotgun shell containing 32 darts and ending with single-round flechette "rifles". Winchester and Springfield offer multi-barrel weapons, while ORO's own design used two .22, .25 or .27 caliber bullets loaded into a single .308 Winchester or .30-06 cartridge. Eugene Stoner Meanwhile testing of the 7.62mm T44 continued, and Fabrique Nationale also submitted their new FN FAL via the American firm of Harrington & Richardson as the T48. However, the results of the testing were apparently already a forgone conclusion; the T44 was selected as the new battle rifle for the U.S. Army (rechristened the M14) despite a strong showing by the T48. Acceptance of the M14 did not occur before a newcomer entered the contest. In 1954, Eugene Stoner of the newly-formed ArmaLite helped develop the 7.62mm AR-10. Springfield's T44 and similar entries were conventional rifles using wood for the "furniture" and otherwise built entirely of steel using mostly forged and machined parts. ArmaLite was founded specifically to bring the latest in designs and alloys to firearms design, and Stoner felt he could easily beat the other offerings. Stoner's AR-10 was radical for its day. The receiver was made of forged and milled aluminum instead of steel. The barrel was mated to the receiver by a separate hardened steel adapter to which the bolt locked. This allowed a lightweight aluminum receiver to be used while still maintaining a steel-on-steel lockup. The bolt was operated by gases vented from the front of the barrel directly into a cylinder created in the bolt carrier with the bolt itself acting as a piston. Traditional rifles located this cylinder and piston close to the gas vent. The stock and grips were made of a fiberglass-reinforced plastic shell over a rigid foam plastic core. The flash suppressor was fabricated from titanium. Over Stoner's vehement objections, various experimental composite and 'Sullaloy' aluminum barrels were fitted to some AR-10 prototypes by Armalite's president, George Sullivan. The Sullaloy barrel was made entirely of heat-treated aluminum, while the composite barrels used aluminum extruded over a thin stainless steel liner. Meanwhile the layout of the gun itself was also somewhat different. Previous designs generally placed the sights directly on the barrel, using a bend in the stock to align the sights at eye level while transferring the recoil down to the shoulder. This meant that the gun tended to rise when fired making it very difficult to control during fully-automatic fire. The ArmaLite team used a solution previously used on weapons such as the German FG42 and Johnson light machine gun; they located the barrel in line with the stock, well below eye level, and raised the sights to eye level. The rear sight was built into a carrying handle over the receiver. The AR-10 was a very advanced design for its time. Despite being over two pounds (900 g) lighter than the competition, it offered significantly greater accuracy and recoil control. Two prototype rifles were delivered to the U.S. Army's Springfield Armory for testing late in 1956. At this time, the U.S. armed forces were already two years into a service rifle evaluation program, and the AR-10 was a newcomer with respect to older, more fully-developed designs. Over Stoner's continued objections, George Sullivan had insisted that both prototypes be fitted with composite aluminum/steel barrels. Shortly after a composite barrel burst on one prototype in 1957, the AR-10 was rejected. The AR-10 was later produced by a Dutch firm, Artillerie Inrichtingen, and saw limited but successful military service with several foreign nations. CONARC In 1957, a copy of Gustafson's funding request from 1955 found its way into the hands of General Willard Wyman, commander of the U.S. Continental Army Command (CONARC). He immediately put together a team to develop a .22 caliber (5.6 mm) weapon for testing. Their finalized request called for a select-fire weapon of 6 pounds (2.7 kg) when loaded with 20 rounds of ammunition. The bullet had to penetrate a standard U.S. steel helmet, body armor, or a 0.135 inch (3.4 mm) steel plate and retain a velocity in excess of the speed of sound at 500 yards (460 m), while equaling or exceeding the "wounding" ability of the .30 Carbine. Having seen the AR-10 in an earlier demonstration, and impressed by its performance, Wyman personally suggested that ArmaLite enter a weapon for testing using a 5.56mm cartridge. Stoner was working on a newer version of the AR-10but others at the company took up the challenge. Their first design, using conventional layout and wooden furniture, proved to be too light. When combined with a conventional stock, recoil was excessive in fully automatic fire. Their second design was simply a scaled-down AR-10, and immediately proved much more controllable. Winchester entered a design based loosely on their M1 Carbine, and Earle Harvey of Springfield attempted to enter a design, but was overruled by his superiors at Springfield, who refused to divert resources from the T44. In the end, ArmaLite's AR-15 really had no competition. The lighter round allowed the rifle to be scaled down, and was smaller and lighter than the previous AR-10. The AR-15 weighed only around 5.5 pounds (2.27 kg) empty, and 6 pounds (2.73 kg) with a loaded (20 round magazine). During testing in March 1958, rainwater caused the barrels of both the ArmaLite and Winchester rifles to burst, causing the Army to once again press for a larger round, this time at .258 inch (6.55 mm). Nevertheless, they suggested continued testing for cold-weather suitability in Alaska. Stoner was later asked to fly in to replace several parts, and when he arrived he found the rifles had been improperly reassembled. When he returned he was surprised to learn that they too had rejected the design even before he had arrived, their report also endorsed the .258 inch (6.55 mm) round. After reading these reports, General Maxwell Taylor became dead-set against the design, and pressed for continued production of the M14. Not all the reports were negative. In a series of mock-combat situations testing the AR-15, M14 and AK-47, the Army found that the AR-15's small size and light weight allowed it to be brought to bear much more quickly, just as CONARC had suggested. Their final conclusion was that an 8-man team equipped with the AR-15 would have the same firepower as a current 11-man team armed with the M14. They also found that the AR-15, as tested, was more reliable than the M14, suffering fewer stoppages and jams in tests where thousands of rounds were fired. At this point, Fairchild had spent $1.45 million in development expenses, and wished to divest itself of its small-arms business. Fairchild sold production rights for the AR-15 to Colt Firearms in December 1959, for only $75,000 cash and a 4.5% royalty on subsequent sales. In 1960, ArmaLite was reorganized, and Stoner left the company. M16 adoption Curtis LeMay viewed a demonstration of the AR-15 in July 1960. He immediately ordered 8,500 for defense at Strategic Air Command airbases, later rescinded by Defense Secretary Robert McNamara. Colt Industries also approached the Advanced Research Projects Agency (ARPA), who bought 1,000 rifles for use by South Vietnamese troops in the early summer of 1962. American special operations units and advisors working with the South Vietnamese troops filed battlefield reports lavishly praising the AR-15 and the stopping effectiveness of the 5.56mm cartridge, and pressed for its adoption. U.S. Secretary of Defense Robert McNamara now had two conflicting views: the ARPA report favoring the AR-15 and the Pentagon's position on the M14. Even President John F. Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army's test report stated only the M14 was suitable for Army use, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used, who reported that the testers showed undue favor to the M14. Secretary Robert McNamara ordered a halt to M14 production in January 1964, after receiving reports that M14 production was insufficient to meet the needs of the armed forces. Secretary McNamara had long been a proponent of weapons program consolidation among the armed services. At the time, the AR-15 was the only rifle that could remotely fufill a requirement of a 'universal' infantry weapon for issue to all services. McNamara ordered the weapon be adopted unmodified, in its current configuration, for immediate issue to all services, despite receiving reports noting several deficiencies with the M16 as a service rifle, including the lack of a chrome-lined bore and chamber, the 5.56mm projectile's instability under arctic conditions, and the fact that large quantities of 5.56mm ammunition required for immediate service were not available. In addition, the Army insisted on the inclusion of a forward assist plunger to help push the bolt into battery in the event that a cartridge failed to seat in the chamber through fouling or corrosion. Such a device had been incorporated into later versions of the AR-10, which also had a chrome-lined chamber to prevent corrosion (Pikula). Colt on the other hand, had argued the rifle was a 'self-cleaning' design, requiring little or no maintenance. Colt, Eugene Stoner, and the U.S. Air Force believed that a forward assist needlessly complicated the rifle and added about $4.50 to its procurement cost, with no real benefit. As a result, the design was split into two variants: the Air Force's M16 without the forward assist, and for the other service branches, the XM16E1 with the forward assist. In November 1964, the Army ordered 85,000 XM16E1s for experimental use, and the Air Force ordered another 19,000. Meanwhile, the Army carried out another project, the Small Arms Weapons Systems (SAWS), on general infantry firearm needs in the immediate future. They highly recommended the immediate adoption of the weapon, so much so that they started referring to it as the M16. Later that year the Air Force officially accepted their first batch as the United States Rifle, Caliber 5.56 mm, M16. The Army began to immediately issue the XM16E1 (re-named M16 on its adoption) to infantry units, and the rifle was initially delivered without adequate cleaning supplies or kit. Moreover, the Army's inability to deliver 5.56mm ammunition meeting quantity and velocity specifications led to a change in powder specification for the 5.56mm cartridge. Unfortunately, the change was made without testing the modified ammunition in the rifle under service conditions. The newly-specified 5.56 ammunition increased the cyclic rate of fire, increasing wear on parts, and the new gunpowder's burning characteristics increased fouling in the M16 rifle. When the XM16E1 reached Vietnam with U.S. troops in 1966, reports of jamming and malfunctions in combat immediately began to surface. Although the M14 had a chrome-lined barrel and chamber to resist corrosion in combat conditions (a danger learned from WWII Pacific theatre combat experience), the M16/XM16E1 had no chrome-lined bore or chamber. Several documented accounts of troops killed by enemy fire with jammed rifles broken-down for cleaning eventually brought a Congressional investigation. Later investigations also cast doubt on the veracity of the original 1962 reports of the alleged stopping effectiveness of the 5.56mm bullet, as well as criticism of inadequate penetration (in comparison to the Soviet 7.62mm x 39mm round) when firing at enemy personnel through light cover. The XM16E1 was soon modified to the M16A1 specification. The revised rifle was finally given a chrome-lined bore and chamber to eliminate corrosion and stuck cartridges, and the rifle's bore and recoil mechanism was re-designed to accommodate Army-issued 5.56mm ammunition. Rifle cleaning tools and powder solvents/lubricants were issued. The Army ordered 840,000 of this version on February 28, 1967. Intensive training programs in weapons cleaning were instituted, and a comic book style manual was circulated among the troops to demonstrate proper maintenance. The reliability problems of the M16 diminished quickly, although the rifle's reputation continued to suffer. Moreover, complaints about the inadequate penetration and stopping power of the 5.56mm cartridge persisted throughout the Vietnam conflict, and continue to this day. NATO standardization In March 1970, the Pentagon shocked other NATO nations by stating all U.S. forces assigned to NATO would be equipped with the M16A1. The British military was highly vocal in voicing its anger after adopting the 7.62 mm NATO round over their .280 caliber (7.1 mm) round nearly 20 years earlier. Now they were being told the U.S. recognized the need for such a caliber of firearm after all, and was willing to start the NATO standardization of a lighter round. But by the middle of the 1970s, other armies were also looking at an M16-style weapon. A NATO standardization effort soon started, and tests of various rounds were carried out starting in 1977. The U.S. offered their original design, the M193, with no modifications, but there were serious concerns about its penetration in the face of the wider introduction of body armor. The British introduced a modified 5.56 mm round, using a longer and thinner bullet of 4.85 mm. The round had somewhat better ballistics, and considerably better penetration, able to reach 600 m and meet their requirements for a squad automatic weapon (small machine gun). The Germans introduced a new 4.7 mm caseless round, which was considerably lighter while offering similar ballistics to the original U.S. design. However, there was distrust in the caseless system due to the possibility of cook off. A final design was offered by the Belgians. Their SS109 round was based on the U.S. cartridge but included a new bullet design with the same 5.56 mm caliber with a small steel tip to improve penetration. Testing soon showed that the British and Belgian designs were roughly equal, both outperforming the original U.S. design. In order to get full performance from tracer versions of the SS109, however, barrels would have to use different rifling. Existing 1-in-12 twist barrels reduced the effective range of the SS109 to 90 meters due to lack of stability. While the ideal twist rate for the SS109 projectile is 1-in-9, a 1-in-7 twist rate was chosen to stabilize the much longer L110 tracer. This tracer was designed to complement the SS109's ballistic performance. The M196 tracer (complement to the M193 ball round) had a burn-out range of 450 meters where the L110 tracer was bright to 800 meters. In the end the Belgian round was chosen. The U.S. Marine Corps was first to adopt the round with the M16A2, introduced in 1982. This was to become the standard U.S. military rifle. The NATO standard ammunition produced for U.S. forces is designated M855 for the ball round using a SS109 type projectile and M856 for the tracer using the L110 type projectile. Total worldwide production of M16-style weapons since the design's inception has been approximately 8 million. Design The M16's receivers are made of aluminum alloy, its barrel, bolt, and bolt carrier of steel, and its handguards, pistol grip, and buttstock of plastics. Early models were especially lightweight at 2.9 kg (6.4 lb). This was significantly less than older 7.62 mm "battle rifles" of the 1950s and 1960s. It also compares very favorably with the 5 kg (loaded) AK-47. M16A2 and later variants weigh more (8.5 lb or 3.9 kg loaded) because of the adoption of a thicker barrel profile. The thicker barrel is more resistant to damage when handled roughly and is also slower to overheat during sustained fire. Unlike a traditional "bull" barrel that is thick its entire length, the M16A2's barrel is only thick forward of the handguards. The barrel profile under the handguards remained the same as the M16A1 for compatibility with the M203 grenade launcher. The rifle is 40 inches (1.02 m) long with standard 20-inch (508 mm) barrel. One distinctive ergonomic feature is a plastic or metal stock directly behind the action, which contains a recoil spring. This serves the dual function of operating spring and recoil buffer. The stock being in line with the bore reduces muzzle rise, especially during automatic fire. Because recoil does not significantly shift the point of aim, user fatigue is reduced. Another distinctive ergonomic feature is that the rear sight is set into a carrying handle on top of the receiver. This design is a by-product of the original design where the carry handle served to protect the charging handle. In practice, the handle is rarely used to carry the weapon; holding the weapon by the pistol grip provides quicker response time while a shoulder sling provides a more convenient option when response time is not a concern. More importantly, with the sight plane 2.5 inches over the bore, the M16 has an inherent parallax problem that can be confounding to shooters. At closer ranges (typically inside 15–20 yards), the shooter must aim high in order to place shots where desired. Newer models have a "flattop" upper receiver with a Picatinny mounting rail, to which the user can attach either a conventional sighting system or numerous optical devices such as night vision scopes. The M16 utilizes direct impingement gas operation; energy from high-pressure gas tapped from a non-adjustable port built into the front sight assembly actuates the moving parts in the weapon. Combustion gases travel directly into a chamber in the bolt carrier behind the bolt itself, pushing the carrier away from the bolt. This reduces the number of moving parts by eliminating the need for a separate piston and cylinder and it provides better performance in rapid fire by keeping reciprocating masses on the same axis as the bore. The primary criticism of direct impingement is that fouling and debris from expended gunpowder is blown directly into the breech. As the superheated combustion gas travels down the tube, it expands and cools, not unlike an aerosol can cools when depressurized. This cooling causes vaporized matter to condense as it cools depositing a much greater volume of solids into the operating components of the action. The amount of sooting deposits tends to vary with powder specification, caliber, and gas port design. Conversely, gas-piston operation uses high-pressure gasses for very short periods of time minimizing gas exposure to the breech. This sooting characteristic had not been found to be a significant hindrance to reliability with Armalite's earlier AR-10 in 7.62mm caliber, which had a different gas port and adjustable gas regulator (Pikula). Because of this sooting, the M16 rifle requires more frequent cleaning and lubrication for reliable operation compared to most gas piston designs. The magazine release is on the right side of the rifle, ahead of the trigger guard. Current military magazines have a capacity of 30 rounds, as opposed to the 20-round magazines issued in Vietnam. (30-round magazines were not developed and issued until late in the war.) Aftermarket double magazine clips are available. This practice is discouraged by military authorities because it is said to increase the chance that the top of a magazine will be damaged or pick up dirt. Nevertheless, recent pictures from Iraq (2004) show that Special Forces and mainstream military forces are quick to make use of double magazine clips. Both the M193 and newer M855 (SS109) bullets may fragment when striking soft tissue or light cover such as small trees. When fired from less than 100 meters, these bullets will penetrate 100 mm (4 in) into body tissue, before yawing 90 to 180 degrees. Fragmentation occurs when lateral forces on the bullet cause it to break in half. This occurs at the weak cannelure, which is a groove allowing the bullet casing to be sealed to the copper jacket. The rear section of the 5.56 mm bullet will then fragment into numerous tiny pieces, causing increased damage to surrounding tissue. The necessary velocity for reliable fragmentation is roughly 823 meters (2,700 feet) per second. The U.S. no longer generally issues fully-automatic M16-style rifles. Even with the relatively light recoil of the M16, the point of aim is still thrown off sufficiently by each round that a fully-automatic rifle would be wildly inaccurate and amount to a waste of ammunition. The 30-round magazine is not suited to sustained fire like the belted feed systems of heavier true machine guns, and the M16's lightweight barrel would overheat quickly under automatic fire. Doctrinally, machine guns deliver suppressing fire to keep the enemy under cover while the more mobile riflemen flank the position and deliver point fire. Some variants of the M4, which is optimised toward close-quarters battle, are capable of fully automatic fire as this makes more sense at the limited ranges encountered in CQB. Most M16 and M4-style weapons issued are capable of semi-automatic fire and 3-round burst. The burst-fire mechanism utilizes a three-part automatic sear that fires up to three rounds for each pull of the trigger. It is non-resetting, meaning that if a soldier fires a two-round burst and releases the trigger, he will encounter a single round fired the next burst. In theory, burst-fire mechanisms allow ammunition conservation for troops with limited training and combat experience, at the cost of a very poor trigger pull. They also tend to limit the weapon's effectiveness when used in suppression, ambush situations, and close-quarters combat. Colt developed a variant with a heavier barrel, belt-feed, and fast barrel replacement. This was intended to provide a squad with the firepower of a machinegun with the portability of the M16. This was canceled in favor of the M249 Squad Automatic Weapon in the 1970s. Squads are now issued the M249 (one per fireteam) to provide automatic fire. Fully-automatic versions (the M16A3 and M4A1) are issued by the U.S. military to certain specialized units. Production and usage The M16 is the most commonly manufactured 5.56 x 45 mm rifle in the world. Currently, the M16/M4 system is in use by 15 NATO countries and more than 80 countries world wide. Together, the U.S. and Canada (as the C7) have produced more than 8,000,000 units with approximately 90% still in operation. In U.S. service, the M16 primarily replaced the M14 and M1 Carbine series as standard infantry rifles, and to a lesser extent, some of the jobs of the BAR Light automatic rifle. The M14 would go on to see service, just not as the primary service rifle. It was used as a sniper rifle and as a designated marksman rifle, as well a several smaller niche areas. Variants AR-15 (Colt Models 601 & 602) Colt's first two models produced after the acquisition of the rifle from ArmaLite were the 601 and 602, and these rifles were in many ways clones of the original ArmaLite rifle (in fact, these rifles were often found stamped Colt ArmaLite AR-15). The 601 and 602 are easily identified by their "slab-sided" lower receivers without the commonly found "fencing" around the magazine well, and in certain cases their green or brown furniture. The 601 was adopted first of any of the rifles by the USAF, and was quickly supplemented with the XM16 (Colt Model 602) and later the M16 (Colt Model 604) as improvements were made. There was also a limited purchase of 602s, and a number of both of these rifles found their way to a number of Special Operations units then operating in South East Asia, most notably the U.S. Navy SEALs. The only major difference between the 601 and 602 is the switch from the original 1:14-inch rifling twist to the more common 1:12-inch twist. M16 Variant originally adopted by the USAF. This was the first M16 adopted operationally. This variant had triangular handguards, a three-pronged flash suppressor, and no forward assist. Bolt carriers were originally chrome plated and slick-sided, lacking any notches for a forward assist. Later, the chrome plated carriers were dropped in favor of Army issued notched and parkerized carriers. The Air Force continues to operate these weapons and upgrades them as parts wear or break and through attrition. XM16E1 and M16A1 The prototype army-version, XM16E1, was essentially the same weapon as the M16 with the addition of a forward assist. The M16A1 was the finalized production model. To address issues raised by the XM16E1's testing cycle, a "bird-cage" flash suppressor replaced the XM16E1's three-pronged flash suppressor, which was too easy for foreign material to get into and which caught on twigs and leaves. After numerous problems in the field, numerous changes were fielded. Cleaning kits were developed and issued; barrels with chromed chambers and later fully-chromed bores were introduced. The number of malfunctions due to fouling and corrosion declined and later troops were generally unfamiliar with early problems. A rib was built into the side of the receiver protecting the magazine release from being inadvertently being pressed. The bolt cam pin and the hole it rides in the bolt were beveled to prevent the bolt from being inserted upside down (creating a failure to eject). M16A2 Modifications to the M16A2 were more extensive. In addition to the new rifling, the barrel was made with a greater thickness in front of the front sight post to resist bending in the field. The front sight was now a square post with 4 detent positions in order to refine the sight picture. A new adjustable rear sight was added, allowing the rear sight to be dialed in for specific range settings between 300 and 800 meters to take full advantage of the ballistic characteristics of the new SS109 rounds and to allow windage adjustments without the need of a tool or cartridge. The flash suppressor was again modified, this time to be closed on the bottom so it would not kick up dirt or snow when being fired from the prone position. The front grip was modified from the original triangular shape to a round one, which better fit smaller hands and could be fit to older models of M16's. The new handguards were also symmetrical so that armories didn't need separate left and right spares. The handguard retention ring was angled to make it easier to install and uninstall the handguards. The pistol grip adds a notch for the middle finger and more texture to enhance the grip. The buttstock was lengthened by 5/8 inches. The new buttstock is said to be ten times stronger than the original due to advances in plastics and design and affixed with a textured polymer buttplate enhancing traction. The heavier bullet has a reduced muzzle velocity from 3,200 feet per second (975 m/s) in the earlier models, to about 3,050 feet per second (930 m/s) in the A2 and required a change in rifling to allow the use of a trajectory-matched tracer round. A special spent case deflector was incorporated into the upper receiver to the rear of the ejection port to prevent spent casings from striking left-handed users. The action was also modified, replacing the fully-automatic setting with a three-round burst setting. When using a fully-automatic weapon, poorly trained troops often hold down the trigger and "spray" when under fire. The U.S. Army concluded that three-shot groups provide an optimum combination of ammunition conservation, accuracy and firepower. There are mechanical flaws in the M16A2 burst mechanism. The trigger group does not reset when the trigger is released. If a soldier lets go of the trigger between the second and third round of the burst, for example, the next trigger pull would only result in a single shot. Even in semi-automatic mode, the trigger group mechanism affects weapon handling. With each round fired, the trigger group cycles through one of the three stages of the burst mechanism. Worse, the trigger pull at each of these stages may vary as much as 6 lbs. in pressure differential, detracting from accuracy. All together, the M16A2s new features added weight and complexity to the M16 while simultaneously decreasing barrel life and removing the full-automatic fire setting. While the new gun was said to be more accurate, the heavier bullets had a more curved trajectory requiring more precise range estimation for accurate shot placement. Critics also point out that neither of the rear sight apertures is ideally sized. The small aperture is too small, making quick acquisition of the front sight post difficult, and the large aperture is too large, resulting in decreased accuracy. To make matters worse, the rear sight apertures are not machined to be on the same plane. In other words, the point of impact changes when the user changes from one aperture to the other. The rear sight's range adjustment feature is rarely used in combat as soldiers tend to leave the rear sight on its lowest range setting: 300 meters. Despite criticism, a new rifle was needed both to comply with NATO standardization of the SS109 (M855) and to replace aging Vietnam era weapons in the inventory. M16A3 The M16A3 was a fully-automatic variant of the M16A2 adopted in small numbers around the time of the introduction of the M16A2, primarily by the U.S. Navy for use by the SEALs. It features a Safe-Semi-Auto (S-1-F) trigger group like that of the M16A1. Some confusion continues to exist regarding the M16A3. It is often described as the fully-automatic version of the M16A4. Descriptions of the M16A3 that claim that it shares the M16A4's Picatinny rail are incorrect. This misunderstanding most likely stems from the usage of the A2 and A3 designations by civilian manufacturers to differentiate between A2-style fixed carry handles and Picatinny rail versions. M16A4 The M16A4, now standard issue for frontline U.S. Army and U.S. Marine Corps units, replaces the combination fixed carry handle/rear iron sight with a MIL-STD-1913 Picatinny rail, allowing for the rifle to be equipped with a carry handle and/or most military and consumer scopes or sighting systems. All of the U.S. Marine Corps' M16A4s are equipped with a Knight's Armament Company M5 RAS handguard, allowing vertical grips, lasers, tactical lights, and other accessories to be attached. U.S. Army M16A4s also often feature the KAC M5 RAS. In U.S. Army Field Manuals, M16A4s fitted with the RAS are sometimes referred to as M16A4 MWS or Modular Weapon System. This model retains the 3-round burst mode of the M16A2. Specialist Variants Colt Model 655 and 656 "Sniper" variants With the expanding conflict in South East Asia, Colt developed two rifles of the M16 pattern for evaluation as possible light sniper or designated marksman rifles. The Colt Model 655 M16A1 Special High Profile was essentially a standard A1 rifle with a heavier barrel and a scope mount that attached to the rifle's carry handle. The Colt Model 656 M16A1 Special Low Profile had a special upper receiver with no carrying handle. Instead, it had a low-profile iron sight adjustable for windage and a Weaver base for mounting a scope, a precursor to the Colt and Picatinny rails. It also had a hooded front iron sight in addition to the heavy barrel. Both rifles came standard with either a Leatherwood/Realist scope 3-9x Adjustable Ranging Telescope. Some of them were fitted with a Sionics noise and flash suppressor. Neither of these rifles were ever standardized. These weapons can be seen in many ways to be predecessors of the U.S. Army's SDM-R and the USMC's SAM-R weapons. XM177, M4 Carbine, and Colt Model 733 In Vietnam, some soldiers were issued a carbine version of the M16 called the XM177. The XM177 had a shorter barrel (~260 mm) and a telescoping stock, which made it substantially more compact. It also possessed a combination flash hider/sound moderator to reduce problems with muzzle flash and loud report. The USAF's GAU-5/A (XM177) and the U.S. Army's XM177E1 variants differed over the latter’s inclusion of a forward assist. The final USAF GAU-5A/A and U.S. Army XM177E2 had a 290 mm barrel with a longer flash/sound suppressor. The lengthening of the barrel was to support the attachment of Colt's own XM148 40 mm grenade launcher. These versions were also known as the Colt Commando model commonly referenced and marketed as the CAR-15. The variants were issued in limited numbers to special forces, helicopter crews, Air Force pilots, officers, radio operators, artillerymen, and troops other than front line riflemen. The M4 Carbine was developed from various outgrowths of these designs, including a number of 14.5-inch-barreled A1 style carbines. The XM4 (Colt Model 720) started its trials in the mid-80s, with a 14.5-inch (368 mm) barrel. Officially adopted as a replacement for the M3 "Grease Gun" (and the Beretta M9 and M16A2 for select troops) in 1994, it was used with great success in the Balkans, the 2000s War on Terrorism, including the Afghanistan and Iraq theaters. It is three round burst on the standard carbine, and full auto on the M4A1 Carbine. Colt also returned to the original "Commando" idea, with its Model 733, essentially a modernized XM177E2 with many of the features introduced on the M16A2. A more complete history of this weapon can be found with other information on the Colt Commando. A Firing Port Weapon or FPW was also developed to work with the Bradley IFV, designated the M231. Mk 4 Mod 0 The Mk 4 Mod 0 was a variant of the M16A1 produced for the U.S. Navy SEALs during the conflict in Vietnam and adopted in April 1970. It differed from the basic M16A1 primarily in being optimized for maritime operations and coming equipped with a sound suppressor. Most of the operating parts of the rifle were coated in Kal-Guard, a quarter-inch hole was drilled through the stock and buffer tube for drainage, and an O-ring was added to the end of the buffer assembly. The weapon could reportedly be carried to the depth of 200 feet (60 m) without damage. The initial Mk 2 Mod 0 Blast Suppressor was based on the U.S. Army's Human Engineering Lab's (HEL) M4 noise suppressor. The HEL M4 vented gas directly from the action, requiring a modified bolt carrier. A gas deflector was added to the charging handle to prevent gas from contacting the user. Thus, the HEL M4 suppressor was permanently mounted though it allowed normal semi-automatic and automatic operation. If the HEL M4 suppressor were removed, the weapon would have to be manually loaded after each single shot. On the other hand, the Mk 2 Mod 0 blast suppressor was considered an integral part of the Mk 4 Mod 0 rifle, but it would function normally if the suppressor were removed. The Mk 2 Mod 0 blast suppressor also drained water much more quickly and did not require any modification to the bolt carrier or to the charging handle. In the late 1970s, the Mk 2 Mod 0 blast suppressor was replaced by the Mk 2 blast suppressor made by Knight's Armament Company (KAC). The KAC suppressor can be fully submerged and water will drain out in less than eight seconds. It will operate without degradation even if the M16A1 is fired at the maximum rate of fire. The U.S. Army replaced the HEL M4 with the much simpler Studies in Operational Negation of Insurgency and Counter-Subversion (SIONICS) MAW-A1 noise and flash suppressor. Quote Link to comment Share on other sites More sharing options...
Got Uzi Posted October 7 Report Share Posted October 7 Out of curiosity-are there any numbers out there on original Colt 635 and 639 SMG guns that are transferable? Were there any that were “slab side” or were those all conversion guns? I recall only seeing conversions but wasn’t sure if original slab side guns existed. Quote Link to comment Share on other sites More sharing options...
MPFiveO Posted October 9 Report Share Posted October 9 By the time the models 635 and 639 came out the lower receiver had been standardized with the A1 upgrades which included the full fence around the magazine release button and no roll pin for the buffer tube. With exception of the 635 all of the 600 series was marked AR-15 Model XXX. The 635 was just marked SMG. The 639 was made in relatively small numbers so while not rare, they are uncommon. I know a buddy who has one but his didn't come with the moderator. ATF collected most of them but they did allow them to be registered as suppressors even though they do an extremely poor job of suppressing. The purpose of the moderator was to knock the decibel level down to that of a 20 inch barrel and it does that but it's still really loud. The 635 is less common than the 639 because it came out much later and much closer to the 1986 ban. I would almost categorize them as rare by the number of transferable ones available. Any slab side versions of these would be conversions or clones someone cobbled together. I recall seeing a "Factory Colt 639 machine gun for sale!" once but pictures showed a converted SP1 receiver and a cut down barrel as evidenced by the presence of a bayonet lug. Quote Link to comment Share on other sites More sharing options...
Got Uzi Posted October 9 Report Share Posted October 9 Thanks for the info. I saw that on the MWT listing today they have an original Colt 9mm SMG listed for $38k….given the amount out there that’s probably not a terrible price given what original Colt M16’s are going for these days. Quote Link to comment Share on other sites More sharing options...
colossians323 Posted October 26 Report Share Posted October 26 On 9/25/2024 at 12:31 AM, Chef said: Everything jbntex said is spot on. The only thing I could add is that factory Colt M16s (in which ever flavor) will appreciate in value better and sell quicker than conversions, rewelds or clones. And considering the amount of money you are spending for any transferable M16 style of firearm, it only makes sense to do whatever you have to do to get the best you can from the start. When you're holding your newly purchased, rough finished Sendra and going through your mag stash to weed out the ones that don't fit well, you'll be wishing you spent the extra money for a factory Colt. For some people there is "pride of ownership". If you feel just as comfortable wearing a fake Rolex as you would wearing a real one, then you probably won't care much if you've got a "factory" M16 or just one that "works". But if wearing that knockoff Rolex would bother you, then there''s a good chance that you'll regret not going all-in and buying the best from the get-go. Not all Sendras are equal? I have a Sendra and several Colt M16's and don't have any problems with my sender fitting magazines. I don't wish I spent more for the colts, I only bought the colts for collector value. I guess I am lucky having the Sendra that fits the magazines and shoots just fine? Quote Link to comment Share on other sites More sharing options...
Chef Posted October 26 Report Share Posted October 26 6 hours ago, colossians323 said: Not all Sendras are equal? I have a Sendra and several Colt M16's and don't have any problems with my sender fitting magazines. I don't wish I spent more for the colts, I only bought the colts for collector value. I guess I am lucky having the Sendra that fits the magazines and shoots just fine? Different strokes for different folks, I guess. Some people buy MGs just to send rounds downrange in FA for the LOLs, and others buy them to have pieces of history, a collectable and shoot FA whenever they get the itch. Clones and tributes have their place, just not with me. I don't need a beater M16 clone or SP1 conversion to loan out to new shooters, or to burn down barrels doing beta mag dumps of tracers. I have originals and I take care of them. Because they give me pride of ownership as collectables as well as being investments. I stand by my statement. YMMV Quote Link to comment Share on other sites More sharing options...
MPFiveO Posted October 26 Report Share Posted October 26 35 minutes ago, Chef said: Different strokes for different folks, I guess. Some people buy MGs just to send rounds downrange in FA for the LOLs, and others buy them to have pieces of history, a collectable and shoot FA whenever they get the itch. Clones and tributes have their place, just not with me. I don't need a beater M16 clone or SP1 conversion to loan out to new shooters, or to burn down barrels doing beta mag dumps of tracers. I have originals and I take care of them. Because they give me pride of ownership as collectables as well as being investments. I stand by my statement. YMMV Everyone is going to have their own opinion on machine gun ownership. I doubt many of us here actually bought machine guns only as investments. The only ones I've ever sold or traded were duplicates that I used to buy other machine guns. For example, I bought several M11/9's when they were cheap, I guess as investments, but with the intention of trading them for others in the future and that's exactly what I did. I traded two of them for a FN FNC converted by S&H Arms. Interestingly, the rate of appreciation has been pretty consistent between the two. At the time I traded, M11/9's were going for about $3500 and FNC's were going for about $7K. Today, two M11/9's will still get you a FNC. So, I didn't really realize any profit on my investment, I just traded two guns for one. From the beginning in 1992 when I bought my first machine gun I never once did so with the intention of selling it for a profit. I still have the first one I bought, a Fleming HK sear. And though it's worth a hundred times what I paid for it I'm still not interested in selling it. And in the years I've owned it I've probably shot well over 100K rounds using it. There's no appreciable wear on it, only a little polishing where the face of the hammer rubs on it. Investing was never part of the plan. It was all about building a collection of guns that were fun to shoot. And I still have fun shooting them. I shoot with a buddy every weekend and just about every weekend I'll bring at least one machine gun. Mostly to let other people shoot but I always put some rounds downrange. As for burners, I have a few. Of my four M16's, one is a conversion. It's the Lego gun in my collection. It can go from XM177 to MK18 in just a few seconds. I probably have half a dozen uppers and stocks for it to change up the configuration. I know it's seen well over 50K rounds and a lot of mag dumps, including Beta's. I don't think less of it, I just think more of my factory Colt's. But I still shoot those too. I have a M11/9 that gets uppers swapped out regularly, one of which takes Suomi drums. Yep, mag dumps. The ones I don't burn down are the FNC and AUG, because of the scarcity of spare parts and barrels. Yeah, the AUG has the advantage over the FNC in that regard but barrels are still way more costly than M16 barrels. If FNC barrels were cheap and easily replaced then it would see a lot more action. As for the historical aspect, I have some of those too. I recently picked up a 1941 produced Reising in the Federal Laboratories case. I have a WWII M3 Grease Gun and a Colt XM16E1 made around 1964. They all make regular trips to the range. I love the history those particular pieces have. But they're definitely not safe queens. I guess I haven't changed my feelings towards machine gun ownership since I got hooked as a teenager when a friend let me shoot a MAC 10 and a M16. My goal in life from that point on was to build a collection that I was proud of and that provided me with all the smiles I could stand. I still get a rush of dopamine when I do a mag dump with the Grease Gun or anything else for that matter. The M16A1 and MAC 10 still do it for me. So, I guess I check all the boxes. Investment, Historical Pieces, and Mag Dumps. 1 Quote Link to comment Share on other sites More sharing options...
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