SA&A AR-15 issues

[ORDuner]

Hey all,

I recently put together a Surplus Ammo and Arms AR-15. I used both a SA&A lower and a SA&A upper (I think the stripped upper is a Aero, but assembled by SA&A). The BCG and LPK is DPMS. I put the lower and an upper together, and went shooting.

Problem 1:
The first thing I noticed was that the bolt would not hold open. I tried several times holding the charging handle back and depressing the bolt release button, but the dang thing just won't stay open. If I depress the bolt-release hard, it will stay open, but as soon as I let off, the bolt closes.

Problem 2:
The next thing I noticed was my polymer mags would not snap into the lower with the bolt closed. When I snap them in with the bolt open, the bolt won't close, and the rounds won't feed. The G.I. spec (stamped metal) mags work fine.

When I use the metal G.I. spec mags, the gun cycles good, but as expected, when the last round is fired, the bolt will not stay open due to problem #1.

I was under the impression these guns usually just pin together and work like a swiss watch. Are there adjustments that can be made to fix these issues?

Thanks

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[Garg]

What type/brand polymer mags are they?
As to the bolt not locking back, did you assemble the lower, or is it a factory lower?

 

[ORDuner]

I bought the lower from a guy on here. He assembled it, and claimed he never fired it. I also bought the mags. second hand. I don't know the brand, but I will double check.

 

[.40cal EMT]

My Precision aero doesn't like Pmags, or Lancer L5, or L5AWM magazines with bolt closed and a full 30 roung mag, easy fix, slam it home pretty hard works for mine.

Do you have another AR upper? Swap it over to the new lower see if you still have that issue. With the bolt catch.

 

[MountainBear]

Problem 1:
The first thing I noticed was that the bolt would not hold open. I tried several times holding the charging handle back and depressing the bolt release button, but the dang thing just won't stay open. If I depress the bolt-release hard, it will stay open, but as soon as I let off, the bolt closes.

Do you have the right buffer? Running a rifle buffer in a carbine tube can cause this issue...

 

[Garg]

Do you have the right buffer? Running a rifle buffer in a carbine tube can cause this issue...

That is a really good question.
Which one does it look like?

AR-15 Buffer Comparison and FAQ

 

[ORDuner]

OK, so I had some time to try a few suggestions.

Problem 1:
I attached a picture of my buffer. It appears to be a carbine buffer. I believe my rifle is a carbine, so that is OK.

I also swapped my old school SP1 upper onto my lower. The bolt still would not hold open. Unfortunatly, I can't put the SP1 lower on my upper b/c the front pin/screw is bigger on the SP1. I'm thinking the problem is with my lower, not the upper.

I'm thinking it could be the catch on the bolt holding mechanism. Or how about a rifle buffer spring? Are they different?

Problem 2:

The magazines are Thermold mags. They don't work in my SP1 either. The Mags will snap in fine, but they won't allow the bolt to close all the way. I could probably push the bolt closed iif my SP1 had a forward assist, but it doesn't. I'm starting to think these Mags are junk.

Keep the suggestions coming, They have all been good and vailid ideas!

Thanks!

 

[Garg]

Sounds like changing the bolt catch would be the next step. Certainly the cheapest... Be careful popping out the bolt catch pin, I would tape all around it, so you do not scratch the lower. I would change the pin, catch, detent, and spring. Just to take a shotgun approach to troubleshooting it.

 

[ORDuner]

I took my rifle down to Curts discount shooters supply, and we figured it out. The buffer tube was bad. I guess it was a cheapo Chinese buffer tube. The bottom of the buffer tube either had something in it, or wasn't drilled out completely. A new buffer tube fixed the problem. Thanks Curt!

 

[iamme]

I took my rifle down to Curts discount shooters supply, and we figured it out. The buffer tube was bad. I guess it was a cheapo Chinese buffer tube. The bottom of the buffer tube either had something in it, or wasn't drilled out completely. A new buffer tube fixed the problem. Thanks Curt!

And this folks is why you a couple bucks more for quality, it saves you in the long run!!! Glad it all worked out.