AR stopped cycling ??

[CP]

It was working fine, then turned into a single shot all of the sudden.  Took the BCG out and it looks fine.  What to check next?

[carpsniperg2]

Buffer and spring? is it picking up the next round out of the mag?

[CP]

No, I don't think the bolt is coming back at all.  I have to hand cycle the next round in.

[carpsniperg2]

My guess would be the loads you are running. Might not have enough power to cycle the action all the way. If you switched recently might be the problem. Check the buffer and spring is that's all good my guess would be the ammunition.

[jay.sharkbait]

Gasblocks tight and timed and is the gastube roll pin installed?

[CP]

Gasblocks tight and timed and is the gastube roll pin installed?

The gas block is loose.  Appears to have migrated forward.

[jay.sharkbait]

Gasblocks tight and timed and is the gastube roll pin installed?

The gas block is loose.  Appears to have migrated forward.

That will do it

[CP]

Radical Firearms upper - The GB is retained with 2 set screws but only one of them left a witness mark on the barrel.  I assume the other one was never tightened.  Nothing that 2 drops of blue Loctite can't fix but clearly a quality problem. 

I hope that fixes it.

[biggfish]

Did you build it or buy it? All the builds I've done there was only one indentation for the set screw the others you just crank into a bit. Perhaps the witness mark you referred to was not the alignment divot.

Sent from my RCT6873W42 using Tapatalk

[carpsniperg2]

I bet they just did not crank it down. You should be good to go now. Most barrel will only have one indent but lock both down for sure.

[hunter399]

Well that was quick,was going to help ,some of the clamp on gb don't even use the indent ,but never had a problem with them so GOODLUCK,if by chance that didn't work clean your gas tube .

[Mongo Hunter]

Good call on the gas block. also check the gas key on the BCG, it should be tight AND staked.

[CP]

I had it on the range yesterday and its cycling again.  I only had one fail-to-feed which I blame on my reloading skills.  The gas block should stay in place now that both set screws are tight with a dab of Loctite on them.

Thanks for all the advice.

[Alchase]

Thanks for posting back with the solution to the problem!