Sign in to follow this  
Followers 0
MindCrime

AR15 SP1 Front Pivot Hole Large to Small conversion work??

Location:

6 posts in this topic

Is there anyone out there that does MilSpec work on AR15/M16 Lower Receivers?  Is there a gun smith out there that can make a Colt SP1 with the Large front pivot hole into a small MilSpec hole for more modern day small hole uppers? I believe M60 Joe use to do this but I believe he is retired now??  

 

Thanks in Advance.

Dan

Edited by MindCrime

Share this post


Link to post
Share on other sites

Personally, I would use adpater pins/bushings (readily available) and not permanently alter either one would be the best option.

 

Edited by Rodney's Distributors

Share this post


Link to post
Share on other sites

Rodney, what kind of luck have you had with bushings? I have a Blue Label Colt HBAR I would like to get a different upper for, but have heard different things about their effectiveness, usually negative. Thanks in advance!

Share this post


Link to post
Share on other sites

I use the AR15/M16 receiver offset adapter pin that www.eabco.net sells for $8.00. 

Share this post


Link to post
Share on other sites

The adapters work fine.  The pin conversion is OK, but you still don't get the front detent that would capture a normal front pin so all it saves is 15 seconds in disassembly and not needing a screwdriver.  I rarely swap uppers since it's still wear and tear on the lower either way on that style lower, and probably less with the offset adapter since it fits tighter IMO.  When I bought that lower it was a $2000 discount from an A1, so for that money I decided I'd pack a screwdriver if needed.  Welding on aluminum lowers is a last resort IMO.  20 years from now you'll be able to accurately 3d print onto an existing lower a new front pin location and have it laser fused vs. a guy in a shop by hand. 

It's going to be shocking what you're going to see "morphed" in the near future, but really cool.  I have a customer that paid 400K for a used metal printer and what you can make is amazing.  25 years ago I had another guy with a "new" stereo lithography machine where rough plastic castings emerged from a bath of goo that needed a lot of final finishing.  Fast forward 10 years and spend more money and the sky is the limit.

Share this post


Link to post
Share on other sites

I agree with Johnson, DONT ATTEMPT ANY WELDING ! unless unavoidable for some other reason. suffer the short falls of the situation and make sure you DONT force it open if the adapter moves. its best not to do much in the way of removal, but of course you must perform mait. I suggest you use one of the offset rear support devices when cleaning to keep the stress off the front hinge. some folks I know used lock tight on the adapters, in an attempt to prevent rotation and the bind.  DONT you will be sorry.  mike


I only accept postal money orders. contact me DIRECTLY before sending any funds                                           email  myoldiron@outlook.com        

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0