AR-15 not cycling/chambering

[Mardayo]

I was able to take the new build to the range today. After the 1st shot of each magazine, the bolt wouldn't chamber the next round. Sometimes, it only pulled the round 1/2 way out of the mag, sometimes fully out of the mag, but never completly chambered. But every time the 1st shot out of the mag was fully ejected - never stove piped.

I was with a buddy who had his AR. I swapped out his bcg, buffer and spring - even swapped out for his mags and ammo but never got past the 1st round. I tried full mags, 1/2 mags and even 2 rounds with every combination with both of our AR's.

Any help would be appreciated. Thanks in advance

 

[J.Boyette]

Re: AR-15 not cycling/chambering

Check the gas block and see if its on right.

I could be loose and canted.

John

 

[cavscout1983]

Re: AR-15 not cycling/chambering

disregard, re-read the post. I was reading it before as if it wasnt ejecting.

 

[sawgunner2001]

Re: AR-15 not cycling/chambering

Feed ramps may need to be polished some. Back in 1998 when I got my very first AR, a Bushmaster V-Match 20", it would only feed from the right side column of the magazine. Sent it back to Bushmaster and when I got it back they had included a copy of the work order which stated that they polished both of the feed ramps. Worked flawlessly till I sold it to my father and is still running strong today.

I'm VERY far from an AR expert, just noting one particular problem I've experienced.

Good luck in getting yours up and running.

 

[exhogflyer]

Re: AR-15 not cycling/chambering

When you say new build, you mean just put together and shot for the first time?Ok, few things to check:
1) try known good mags...maybe borrow a friends that work correctly in another AR
2) could be gas block hole not lined up with hole in barrel..too far left or right, too far back or forward
3) check to make sure the feedramps are compatible...M4 in upper NEEDS M4 in barrel,M4 in barrel will work with any upper.
4) check ammo, if these are reloads make sure they were full length sized and fit in chamber
5) make sure you don't have a rifle length buffer spring in a carbine length tube

 

[Mardayo]

Re: AR-15 not cycling/chambering

Yes it is the first time I'm shooting it.

The mags I have worked fine in my buddy's AR and I tried his mag too.

As far a ammo we were both shooting factory ammo.

I bought the upper with the barrel on it. It was second hand but worked befor I got it.

The only thing I did to the upper is change the gas block, so I'm thinking that's were the trouble is.

Thanks for all the help.

 

[PistonPete]

Re: AR-15 not cycling/chambering

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"><span style="font-size: 17pt"><span style="font-weight: bold"><span style="color: #FF0000">But every time the 1st shot out of the mag was fully ejected - never stove piped</span></span></span></div></div>

so you are saying the next 19 or 29 rounds fired successfully ?? it was only on the first round ? was it from the right or left side or both sides ?

 

[Mardayo]

Re: AR-15 not cycling/chambering

No with the the rifle unloaded I would put a loaded mag in either with the bcg back and release it or pull the charging handle back to cycle in the first round. That round (number one) fired fine and ejected fine, that's when the rifle would not cycle. I never got to round number two.

 

[sobrbiker883]

Re: AR-15 not cycling/chambering

If it will feed from a bolt pulled to the rear manually, but not cycle, its short stroking.

Short stroking doesn't always stovepipe the ejecting round.
Check all the gas components, starting with the gasblock all the way through to the rings.
What buffer and spring, what length barrel with what length gas system?

 

[Mardayo]

Re: AR-15 not cycling/chambering

It's a 16" barrel. I don't know the length gas system. As for the buffer & spring I swapped with my buddy and mine worked fine in his rifle.

 

[match308]

Re: AR-15 not cycling/chambering

Check gas port alignment/make sure you have quality buffer and buffer spring/ use Pmag or mil mag w/magpul follower. And lube the hell out of her.

 

[sobrbiker883]

Re: AR-15 not cycling/chambering

Back to post #2, I'd bet its gas port alignment as well.

 

[Mardayo]

Re: AR-15 not cycling/chambering

That's what I'm thinking. Thanks to you all for the help.

 

[dr800]

Re: AR-15 not cycling/chambering

Had the same issue on a build some time ago. Turns out I forgot to leave a gap between the gas block (PRI with cross-bolts) and barrel-shoulder which is usually filled by the front hand-guard mount. Just enough pressure to extract but it would short-stroke and fail to feed.

 

[Mardayo]

Re: AR-15 not cycling/chambering

Thanks DR800 I'll check it out.