AR-15 question/help

[Unforgiven826]

Ok it has been 25 years since I have fired an M16 in the service. I just bought an AR-15 M4 it is a Stag Arms 2H upper on a CMMG lower all new. My question is, "and I can't remember for the life of me" when firing and the magazine is empty is the bolt supposed to lock to the rear? Also does it lock back far enough that when you insert a new magazine and let the bolt go forward is it supposed to strip a round from the magazine. The reason I ask is that my bolt won't lock to the rear unless I manually lock it and it seem that is does not lock far enough back to strip a new round. I most likely can attribute the locking problem to the old crappy mags a friend gave me. I have some new mags on the way. Thanks for any info you might have.

 

[Bottom Gun]

An empty magazine should lock the bolt carrier fully to the rear.

 

[DMK]

Could be the mags. Could be that the bolt hold open catch is too tight.

 

[Zach S]

Yes, the bolt is supposed to lock, and it should strip a round from a fresh mag when you hit the bolt catch.

Take the upper off and see how freely the bolt catch moves. Make sure its cocked or the bolt catch might drag on the hammer and let you think it isnt moving freely.

By manually locking the bolt back, are you hitting the bolt catch with your finger or using an empty magazine? A weak spring might lock the bolt back when cycling by hand, but may not when firing.

Good mags are a great investment. I got ten, NIW, from ammoman.com for $149 shipped.

 

[rdaines]

I had the mag catch/release bust off once, took me a while to notice. An easy repair but I had a smith do it. It was kind of fiddly with small part and spring. Not an uncommon part to have break.

 

[Bartholomew Roberts]

Does it lock back on the same magazine when you cycle it by hand with an empty magazine? If it does not, then the magazine is probably the issue. If it does, then the bolt may be short-stroking (which usually means not enough gas; but can also happen from too much pressure in the chamber during cycling).

 

[Unforgiven826]

OK I believe my mags are crap. I just ordered 6 new HK high reliability mags. Here is my next problem I think. I can lock the bolt back manually but the carrier and bolt seem to be locked to far forward for it to be able to strip a round from a loaded magazine. Below is a pic of what I see.
or is this normal. Do I need to just pull back on the charging handle after inserting a loaded mag to strip a new round. Any ways I can't remember how it was back in the service. Thanks for helping out an old fart with some timers disease

 

[RRTX]

From that pic the bolt catch is catching the wrong place. It should be catching at the front of the bolt and not on the carrier like it is there. I'm having a brain fart on what all could be causing it, but if it has an collapsible stock make sure it doesn't have a rifle length buffer in it. (Rifle buffer is about 6" long, carbine buffer is only about 3")

 

[Unforgiven826]

RTTX Thanks for the info. I check and it seems that my buffer is about 1/4 inch to long. It me right measures right at 3 1/4 inch long. I guess I need to find a shorter buffer. Thanks for the help

 

[Unforgiven826]

Problem is solved and I feel like a retard. Here is what I found in my buffer tube 3/8 inch or so of junk. Thanks for the help and recommendations.

 

[RRTX]

Glad you got it fixed, I do kind of wonder how that much crap got into the buffer tube though.