SW76 MK760 22LR Conversion Kit

[subgun24]

I designed a 22LR conversion kit for the Smith & Wesson 76 / MK760 submachine gun. Let me know what you think and if it's something you would be interested in.

Video of 20 round burst

https://www.youtube.com/shorts/mC20UPJAhl0

Video of Magazine Loading up close

https://www.youtube.com/shorts/HBrOSDpatCU

 

[KickStand]

I really hope to get one of these. 
 

You need an adapter for the lightnin grip

loader. It’s a game changer. 

[subgun24]

Good suggestion. I will design the lighting adapter and test that out.

[Got Uzi]

Very nice indeed. I’m working on the drawings to do one for a Swedish K. I’d be interested in how you did your magazines as they are very similar. 

[subgun24]

My magazine would probably just take a little tweaking for the Swed K. You welcome to use my mags for your kit. They are made of seven 3D printed parts, a spring and  metal feed lips.

[rcortland]

I see you've also got a placeholder item on your website for a Sterling Mk4 .22 kit.  I will be following both that and the S&W 76 kit with great interest!

[MPFiveO]

Following this with great interest.

[Bill in Bama]

I'm very interested, please keep us posted. 

[Rick Lee]

Also interested in this.

[davester]

My Swede K will want one!  Keep us posted.

[BECFA]

I'd be in for 1 Each

[subgun24]

I have just posted some closeup footage of a 20 round mag dump with slow motion as well.

 

[eMGunslinger]

Any MG that has a 22 kit is always a win, nice work the feeding and ejection looks really nice.

[MPFiveO]

So, some follow up questions. Who made the test gun? What ammo are you running?

*I looked more closely and could see the MKA on the magazine well. Is this a Fruithurst, AL gun or California gun?

Edited June 25, 2025 by MPFiveO
Update

[subgun24]

This particular gun is an Irvine MK760. I have two MK760s and a SW76 as well. Initial design was designed around the MK760. Then, when I tested it in SW76 it needed some minor design changes. After I got it to work in the SW76, the MK760s still ran as well. The only differences I had between the two Mk760s was that the mag well had some dimensional differences. But as long as the mag fit the smaller dimension, all was good in all three guns.

The ammo I use is Aguila 40 grain High Velocity. It is the cheapest ammo and I find that it works great. 

[MPFiveO]

You zeroed in on exactly what my concern was. I have a Fruithurst MK760 and a Panama City 76A1. They are the same gun but different dimensions. I'd be happy to test the kit in my guns if you want some feedback. I'm retired with all the range time in the world.

I also have piles of .22 ammo including the stinky primer Aguila.

[PartTime379]

Very nice.

[john]

I like the project too and would be interested in a kit and some mags too.

I have a SW76 that runs great, has a lotta rounds through it. Have two '28 Thompsons with .22 just and they are a blast to play with!

So, I would love to be able to run .22 through that 76.

Also love to find a .22 kit for my Sten Mk II if anyone is considering that platform.

 

Question.....how do you get the steel lips in a 3D printed mag? Are they sturdy enough to last awhile?

 

Edited July 10, 2025 by john
Sp

[subgun24]

The magazine design is one of the strength of the kit. The steel feed lips will essentially last forever. It is 1mm thick chromoly steel.

Question for you, what color magazine would you prefer? I am thinking a light grey or dark gray although I do like the blue a lot.

I am making a similar kit for the Sterling. It's possible that I would be able to adapt it to work with a Sten.

[22eley]

10 hours ago, subgun24 said:

The magazine design is one of the strength of the kit. The steel feed lips will essentially last forever. It is 1mm thick chromoly steel.

Question for you, what color magazine would you prefer? I am thinking a light grey or dark gray although I do like the blue a lot.

I am making a similar kit for the Sterling. It's possible that I would be able to adapt it to work with a Sten.

Blue! is cool BUT I am LAZY I want EXTRAs, even if i an NOT shooting a machine gun at the range i take 1 so if some kids show up I let them shoot one. and 1 magazine just doesn't work, no matter what caliber the gun is in. Thanks john

[OhioBrett]

On 7/6/2025 at 8:32 PM, john said:

I like the project too and would be interested in a kit and some mags too.

I have a SW76 that runs great, has a lotta rounds through it. Have two '28 Thompsons with .22 just and they are a blast to play with!

So, I would love to be able to run .22 through that 76.

Also love to find a .22 kit for my Sten Mk III if anyone is considering that platform.

 

Question.....how do you get the steel lips in a 3D printed mag? Are they sturdy enough to last awhile?

 

I need a Mk. II one...

[john]

I like the gray park color of the SW76 but most of my mags are Suomi and Swede K mags.

I guess dark gray or maybe even black would be fine. I'd probably run a 400 or 600 grit sanding pad in a finishing sander to dull the shiny surface, as that's a "look" that would match the gun......give mags a nice, flat finish.

As for the Sten, the Sterling mags are quite different and I don't think that would work for Stens......but considering the sheer numbers of Stens on the NFA, that would be a worthwhile project, IMHO.

Might also like the option to buy a magazine tip, maybe 6" long with a follower as there are so many 50 round plastic drums available now that someone like me could refit the mag end onto for a larger capacity.

Or maybe try adding length to yours to give them 50 round capacity......like a Lanchester mag. That would be an easy modification that adds to the fun!

Edited July 10, 2025 by john
Sp

[Bill in VA]

I’d love a .22 kit for my Sterling!

[r6487]

how could I get a single MK760 22 mag to prototype adapting to an E&L drum such as this one does for an HK91.

 

 

[subgun24]

I have the McFadden Lightning Grip Loader adapter ready to go

SW76 Lightning Loader on YouTube

[22eley]

On 6/24/2025 at 3:56 PM, subgun24 said:

I have just posted some closeup footage of a 20 round mag dump with slow motion as well.

 

Hi its john. What day do i get mine with the 6 mags and the Stock kit ??? still waiting! Pictures GREAT but like the Stock conversion , IF your Never going to make them OR dont have them For Sale why show off ? we ALL know you have 1 already running! and you know what your doing. ps i i do like the mount and the fast shipping, thanks.john

Edited July 20, 2025 by 22eley

[subgun24]

Hi John

I assure you the kits are coming very soon, I have all the parts on order however these things take time.

These are some of the actual production parts I have in so far. Barrels, sear catch and trunnion cap. Waiting on the bolt, springs and trunnion.

I haven't ordered the wire stock adapter I promised you but will get that going this week and will take about 3 weeks to arrive.. 

[22eley]

HI, thanks for info. But I  still want that Stock just like you use on your gun ASAP ? thanks a bunch john

[Blanksguy1]

I am interested as well........prices once they are ready for ordering.......and how to get on an order list (?).

[Greasegunner]

I am also interested in a 22 kit for my 76

keep us posted

 

[subgun24]

 

I tested standard velocity Monarch 40 grain soft led bullet and Aguila High Velocity 40 grain copper jacketed bullet in the new M76 - 22LR conversion kit. Both ammunitions are cheap and operate great.

Aguila 765 round per minute

Monarch 735 round per minute

Video on YouTube

[22eley]

16 hours ago, subgun24 said:

 

I tested standard velocity Monarch 40 grain soft led bullet and Aguila High Velocity 40 grain copper jacketed bullet in the new M76 - 22LR conversion kit. Both ammunitions are cheap and operate great.

Aguila 765 round per minute

Monarch 735 round per minute

Video on YouTube

I still am waiting for my 22lr and that STOCK for my 76 i want that asap thanks john

[Chef]

I see you have a Beretta 12 as your profile pic.
Any chance you're working on a .22 kit for it?

[subgun24]

Do you have a PM12 as well? I am thinking about doing a PM12 kit. As soon as I figure out a barrel or barrel liner. Anyone have a suggestion on a PM12 barrel in 22lr?? 

[Chef]

4 hours ago, subgun24 said:

Do you have a PM12 as well? I am thinking about doing a PM12 kit. As soon as I figure out a barrel or barrel liner. Anyone have a suggestion on a PM12 barrel in 22lr?? 

Yes, I have a PM12s. .22 kits for all the things!

[subgun24]

I am now taking orders to the M76 - 22LR kit. $1510 shipped, includes

Kit comes as shown in photo plus three 40 round magazines plus a loader tool. The case will be gray. Magazines can be gray, black or blue.

I did the final testing today and I stand by the statement that it's the best performing 22LR full auto I have ever shot. I am backing that with a 30 day complete return/refund to that effect.

Please PM me if you are interested. 

[rcortland]

I've just ordered!  Do these use the same extractor as the Uzi kits, G3 kits, etc.?  It's hard to tell but it looks like it.

[subgun24]

Thanks.   Yeah they use the UZI / HK extractor available from Bowers.

I am posting better images on the accessories market board.

Edited August 15, 2025 by subgun24
Added info

[Don.]

That’s bad ass!  Well done, sir!!

[rcortland]

In the other thread you mentioned these mags likely working in the Uzi .22 conversions.  If that's true you might consider looking at using your magazines in the G3 .22 kits.  Black Dog Machine has a G3 adapter for their Uzi mags ... but those mags kind of suck.  I've got a better feeling about your magazines with the steel feed lips.

Once I get my SW76 kit I'll likely order some extra magazines and play around with mounting one in a G3 mag body.  The G3 .22 magazines are scarce and only 20 rounds -- a reliable 40 round option would be amazing.  I have two G3 .22 kits (one chopped down for a G3K) and they're both the most reliable FA .22 kits I've shot.  Although I don't have your M76 kit yet so maybe that changes! 

[subgun24]

5 hours ago, rcortland said:

In the other thread you mentioned these mags likely working in the Uzi .22 conversions.  If that's true you might consider looking at using your magazines in the G3 .22 kits.  Black Dog Machine has a G3 adapter for their Uzi mags ... but those mags kind of suck.  I've got a better feeling about your magazines with the steel feed lips.

Once I get my SW76 kit I'll likely order some extra magazines and play around with mounting one in a G3 mag body.  The G3 .22 magazines are scarce and only 20 rounds -- a reliable 40 round option would be amazing.  I have two G3 .22 kits (one chopped down for a G3K) and they're both the most reliable FA .22 kits I've shot.  Although I don't have your M76 kit yet so maybe that changes! 

The M76 mags wont work in the UZI but I have UZI mags that are made very similarly.

For the G3 / HK91 / HK51....You should PM @Grasshopper He has the best G3 22LR Magazines on this planet and I think he is putting metal feed lips on them which will make them even better. He used them in the subgun match today.

 

[subgun24]

Just posted an installation video in case anyone wants to see how the kit goes into the gun.

M76 22LR Installation on YouTube

[Double Tap Firearms]

Nice

Crap sold my Mk 760

Will try it in my Burgess 

Thanks 

[mike in pa]

Is it safe to assume that this will work in a "T" tool room gun?  Will an extended and threaded barrel be available? 

Edited August 18, 2025 by mike in pa

[subgun24]

Yes.  Should work with all S&W 76 variants.  Won’t work with stemple tube guns but I am working on seeing what I can do to make a kit that will work with those. 
 

no plans for threaded barrel.  

[subgun24]

Stemple SW76 9mm owners. I anticipate that I will need to have a new bolt made for the Burgess SW76 guns. Wanted to see how many owners of that firearm would be interested in a 22LR kit so I have an idea of how many to order?

[Double Tap Firearms]

Hello, if everything works out with the first one I might have you build a second one for the other gun I have. 

Thanks 

[Bill in Bama]

I'm waiting "somewhat" patiently for my kit, looking forward to burning up some of the thousands of 22 rounds I have.  Since insole my Lakeside Machine upper I have few options for massive mag dumps.

[subgun24]

Thanks Bill for being patient.  Sending these out as fast as I can get them boxed.  Yours will ship Monday.  
 

a quick note, I originally discouraged CCI ammo.  Now that I have had a chance to test CCI I am switching to a “recommend CCI”.  It worked great and ran clean.  
 

to only ammo to watch out for is thin brass stuff.  Like Winchester Game and Target.  

[22eley]

On 6/17/2025 at 7:57 PM, subgun24 said:

I designed a 22LR conversion kit for the Smith & Wesson 76 / MK760 submachine gun. Let me know what you think and if it's something you would be interested in.

Video of 20 round burst

https://www.youtube.com/shorts/mC20UPJAhl0

Video of Magazine Loading up close

https://www.youtube.com/shorts/HBrOSDpatCU

 

Just put his 22lr kit on my S&W 76 EasyPeasy insulation and i did  NOT read Instructions, SUNDAY is a Day we shoot it! thanks, john PS wish i had a STOCK

[subgun24]

Looks awesome. Thanks for the feedback. Looking forward to hearing how it performs for you.

PS...Sending you a stock and your loader tool on Monday. 

[Bill in Bama]

18 hours ago, subgun24 said:

Thanks Bill for being patient.  Sending these out as fast as I can get them boxed.  Yours will ship Monday.  
 

a quick note, I originally discouraged CCI ammo.  Now that I have had a chance to test CCI I am switching to a “recommend CCI”.  It worked great and ran clean.  
 

to only ammo to watch out for is thin brass stuff.  Like Winchester Game and Target.  

That's good to know since my LM7 preferred CCI Blazer and I have lots of it.

[subgun24]

Mark Shepherd sent me this video of him shooting his M76 22LR in his MK760 for the first time. Thanks Mark 

https://youtube.com/shorts/f5hEnmnjx3E

[Chef]

That's got a nice ROF!

[KickStand]

 

Guys, Christmas came early!

This entire kit, is a work of Art.

 

 

First short test!

This thing is Awesome!

Makes some fireworks at dusk too (I couldn’t see anything with my glasses).

 

 

Edited September 3, 2025 by KickStand

[Bill in Bama]

I got mine today too, was sitting on jy porch when I returned from the hospital,  outpatient surgery will keep me from trying it out until at least Thursday,  but I have no doubt it will be a winner from the videos I've seen. Thanks, Todd, youu are a true Craftsman and I predict you will be busy for a good while. 

[Bill in Bama]

I managed to test fire in my basement today,  runs great and I'm going to have to rethink my ammo , might not have enough after all. 

[KickStand]

Today, I put around 800 rounds through this 22 kit. I tested these manufacturers today Remington Thunderbolt (Bulk), Federal 36gr hollow point (white 50 round boxes) and Federal auto match (bulk, this won’t run in my Lage 22 kit).

This kit runs like a dream and the rate of fire is perfect!

Video below of today’s testing and I’ll be testing more ammo manufactures too (stay tuned)!

 

 

[Bill in Bama]

Was I dreaming or did I see a video somewhere of a loader for 22 ammo that works with Todd 's magazines? Loading 40 rounds time six is not fun.

[subgun24]

Hi Bill.  I am working on an adapter for the McFadden lightning grip loader.  It is about 90% ready. As soon as I have it ready I’ll let you know.