AR-15 rounds sticking in chamber (without firing)

E

esmith

New member
Little background, will try not to ramble. I'm loading some test loads for the new Dtech AR (5.56 short throat chamber). I'm coming up with some odd stuck rounds when I load one on the press, put it in a magazine and chamber it, on some unlikely dimensioned rounds they become stuck and I cannot pull the bolt handle rearward by hand without tapping on the handle with a soft hammer.

Compared to some test loads, this morning for example I was loading some fouling rounds, and these rounds have a shorter Ogive and also a shorter COAL, and they become stuck in the chamber (I have not fired any this way, looking for answers as this doesn't make any sense to me).

The brass is at minimum trim length 1.750''. I've chamber brushed the gun while cleaning and it is still almost unfired at about 40 rounds total.

I'm at a loss for what else could be happening here. What am I missing? What other information do you need to get a better idea?

The round on the left chambers and ejects perfectly, and its altogether longer than the round on the right, which becomes stuck.

 
It's quite possible that you don't have an OAL problem, but a case sizing problem

How far have you bumped your shoulder back?

I usually bump mine about .0015" to .0002" I know some guys go a little further than that. Also, some people swear by small base dies for AR's, I've not had to do that but that's simply my experience.
 
I had the same issue, I would setup my sizing die using my savage112(223) to check a case. Everything good to go until a couple would not chamber in my bushmaster (556). I ordered a wilson case gauge and check those rounds they did not fit between the steps, now I setup die to size case to fit case gauge no more problems inter change between guns. May not be best for benchrest shooting but is what I need for hunting with same ammo for 2 rifles.
 
I have to agree with big on this. I haven't started reloading for my AR yet but when I reload with my bolt actions, if I don't get the headspace right, it'll be difficult if not impossible for me to close the bolt. Looking at your picture too, and maybe this is just because of the picture, but the right round looks longer to where the shoulder starts than the left round. You'd really need to measure that to be sure though.
 
The shoulders need sized back further. Take some empties and turn the die in an eighth. Do a couple and try them in your chamber. Keep turning it in until they eject easily. You can do this with the upper removed.

The Hornady head space tool would be a good investment to prevent this issue. .

Greg
 
I would guess you need to bump the shoulder a little more or need a small base die but shoulder issue gets my vote Wilson case gauge is a big help.
 
What he said. I had the same issue with a .17-.223. Small base sizing die did not help. When I set the die so the press handle cammed over with a good bit of resistance, the problem went away.
 
Originally Posted By: varhunterI have to agree with big on this. I haven't started reloading for my AR yet but when I reload with my bolt actions, if I don't get the headspace right, it'll be difficult if not impossible for me to close the bolt. Looking at your picture too, and maybe this is just because of the picture, but the right round looks longer to where the shoulder starts than the left round. You'd really need to measure that to be sure though.

Good eye, and likely the culprit.
 
Sure enough. Did something I haven't had to do in a long time. Case gauged the offending rounds and the case head was maybe 2-3 mils or less proud of the gauge.

Sized them after setting the die again. They chamber and eject fine now. I found a few more empty cases in the batch the same way. Sized and loaded. Extracted fine.

Sizing die had to have worked loose and I didnt catch it when I ran that batch of brass. I've caught loose dies before they were a problem before so the idea of this problem being caused by a loose die wasnt on my radar.

Thanks for stirring up ideas everyone.
 
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Originally Posted By: GLShooterThe shoulders need sized back further. Take some empties and turn the die in an eighth. Do a couple and try them in your chamber. Keep turning it in until they eject easily. You can do this with the upper removed.

The Hornady head space tool would be a good investment to prevent this issue. .

Greg


Bingo!!
 
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