Sunday, February 28, 2016

Building another AR, a small detail.....

Building an AR15 is fun.  The old stoner design is easily worked on, and not much is needed to do the job.  Parts swap is little harder than putting together a Mr. Potato Head toy.  Even *I* can do this... and that means almost anyone can.

Still, the AR design does hide a few $%#@!^& surprises for the neophyte, and has been known to have an old fart like me say some unkind things as well.  Chief among those for the Old Fat Man... the blasted spring underneath the buttstock plate.

The first time I ever removed an AR buttstock... well.... lets just say this ancient house has a LOT of hardware hidden in the cracks of the wood flooring, and there is a tiny bleeping spring down there keeping it all company.

The spring is there to push on a detent for an action pin. Not a complicated or precise job, it just serves to put pressure on the pin so it won't fall out on it's own.  It's housed in an equally tiny hole drilled through the lower receiver, and the buttstock plate holds the spring in place once it's assembled.

In other words, every time one takes off the buttstock, there is a miniature little partially invisible component that's under pressure there, just waiting to zing off into parts unknown and bring forth an exceptionally unfriendly verbal barrage from the would-be stock swapper.

Trying to outsmart the design, I decided to deal with it before I even began putting the guts in this Rock River lower.  It's a hole, with a spring in it, and it's not rocket surgery.  It just needs something to keep it there.  Enter: a 4x40x1/8" set screw.... and a little 4x40 NC tap to make it fit.

This tap is a perfect fit for the hole.  So much so, that I ran the tap into the hole using nothing more than the multi-tool from my belt to grip it.  In fact, I did it in my lap, while also chatting on the confuser, and had the plug installed in less than 5 minutes.  The tap cut cleanly even while dry, almost scarily easy.   

The tap and drill set, along with the vanishingly tiny plugs, came from Amazon.  With less than $15 expended, I have the tools and parts to do the trick on this and the next three rifles I build.

I'm hoping the rest of the build goes this sweet!

(Now.... can someone point to where I might buy an A2 or A3 complete upper that doesn't cost more than just buying a whole new rifle?)


Long Island Mike said...

Wow... have you on my Netvibes feeds and YOU ARE BACK. Missed your posts. Really. Every now and again would be great ! Wishing you the best !

As to lower cost uppers...check out Palmetto State. They get positive reviews and the prices are pretty nice...

Jason said...

I like Palmetto State Armory. good gear at good prices

TommyG said...

CDNN may not have the style you want but their prices are good. An upper only sells for around $300 and you can by a kit that includes every thing you need except for a lower for $400. Also you should check Aim Surplus they often have uppers under around $250.

Roger said...

Glad to see you posting again. You may recall me from back when you posted regularly.
I have read your old post about your H&R top break .38 revolver.
I am looking for an assembly and parts information on one given to me in pieces and missing a few pieces. Numrich has the parts but how they assemble is difficult to figure out from Numrich's parts page.
Do you have or can direct me to this information?


Carteach said...


The NRA used to publish books on firearms takedown procedures, with good diagrams and instructions. I don't know if they still do, but it would be worth hunting up some of the old ones. The did one for pistols, and another for rifles and shotguns.

My copies have come in bloody handy at times.

Christopher Campagna said...

First, brilliant idea. Come to think of it, if I cut a couple of coils off the selector/safety detention spring, I could do the same and not have to worry about eomovong the grip.

Second, try Model 1 sales for complete uppers. PSA won't ship to me because I live in a Communist state...for now.

Third. Good to see you posting again. I've enjoyed reading all of your, now, uistoical documents.

ASM826 said...

Glad to see you posting again. I have been through a personal shitstorm since we last talked, but it's good to see you back on your blog.

Will said...

I have a vague recollection that this set screw mod requires a shorter spring, to avoid coil-bind that can cause problems with function.
A friend did an 80% receiver at the machine shop that made them. Some sort of builders party, and I tagged along. That mod was done as part of the festivities, with boxes of setscrews and springs. I can't check with him to verify, as he died shortly after that build, sigh...

Anonymous said...

Hi, I am new to your blogg and have really enjoyed it. Your posts on building the AR has been very helpful.

Do have a question for you. Did you clip any coils from the spring for the set screw modification?


Carteach said...

Houston, I thought I might have to, but found they work just fine as is. YMMV

Anonymous said...

Thanks Carteach.