AR-15 BS Thread

Speaking of barrel nut torque, I'm getting ready to put together my AR25 (what I'm calling it since it's not an SR25, don't get all worked up). What torque would you say is appropriate? I forget what I put on my .300 blk build, but that one was specified by geissele. I wanna say it was in the neighborhood of 80 ftlbs, but that sounds like a lot.

 

40-80 ftlbs. I torque three times to 40-60 as a rule.

 

I went with the Sons of Liberty Blaster LPK for a lot of my lowers. They use cast, forged, and hardened parts, not MIM, and made in the USA. You won't need antiwalk pins. I've NEVER seen a trigger or hammer pin fall out. Plus the Larue MBT pins have the cutouts in them, that keep them lined up in your receiver. They look cool though.

 

Thanks, glad I wasn't far off. I'll probably do the same 50-70 two or three times since it's a .308.

 

The Samson rail I just put on said between 40-80 ft/lbs

 

My PSA billet ar-9 lower from day one would have the trigger and hammer pins walk out after 15 rounds. Not all lower brands are equal is what I learned that day. Bought some anti walk pins off eBay for $8 and problem solved. Been good like that for 5 years now and probably couple thousand rounds.

 

That's the first I've heard of that. I've owned many many variants of ARs over the years and shot with friends that have ARs, and have never seen pins walk out. I've never owned a PSA lower either though. I currently have an Anderson, Ruger and Larue lowers and they have all been great with the MBT triggers dropped in em.

 

This is correct as the barrel needs to seat before final torque

 

Out of stock everywhere.

I may just swap my anti-walk pins over to the good gun and use the LaRue pins on the old one. Nothing magical about all the other small parts, although I'd like an ambidextrous safety. Some kits come with the anti-walk pins, but man, some are like 80 bucks! Crazy times, but I am in no hurry, just fidgety.

 

I built another psa gun for a friend for his bday and the pins in it where fine. Sometimes you just get one that the quality control officer was hungover that morning haha. This was a factory built lower btw.
Non of the other many lowers of various brands have this issue

 

I do have a PSA upper on my wife's Anderson lower. That gun shoots sub MOA surpisingly.

 

ive always done 50 as a middle ground, but it all depends - some require proper timing to install the handguard

even radian stated 50 in their handbook

 

Please sir my poor eyes are blinded

 

My wife’s SPR pins used to walk out. I think it was more of the cmmg problem though because it doesn’t walk out after I threw a Triggertech in.

 

Like many manufacturers, PSA outsources the machining of a lot of their parts. In terms of sticking to tolerances however, they are the least demanding of the manufacturers that I've seen. Barret goes way over the top, and rejects parts for the slightest reason. There is a box of Barret lowers and handguards sitting in the vault at work with tiny blems that PSA wouldn't even glance at... There are a few dimensions on Barret handguards that must be within +/- 0.0003", while pretty much everything on a PSA handguard is within +/- 0.003-0.005" though I've seen some go at +/- 0.010" over nominal.

 

So I’ve been wanting a 12.5… now I’m thinking I might as well find someone to pin and weld a 13.7 for me and miss all the paperwork that goes with a 12.5 lol

 

My thoughts exactly

 

Most factory blowback guns use buffers that don't weigh nearly enough. This will beat the hell out of the FCG, among other things Try a heavier buffer and the pins won't move as much because the bolt isn't getting violently slammed back and forth.

I have 10oz buffers in all my 9mm blowbacks.

 

There is a spikes 9mm buffer in there now. it's heavier and longer.

 

Nah. Even their "heavy" version is only 7 oz.

https://www.kawvalleyprecision.com/KVP-10oz-Tungsten-Blowback-Buffer-p/kvp-10oz.htm

I use these KAK weights as well.

https://www.kakindustry.com/9mm-carrier-weight-extra-heavy