223 rolled shoulder when chambering

[cephas]

Is case collapsing when the bullet is being seated? Might want to measure the neck wall thickness of a fired case. Old time way was to take a bullet and see if it slips into the neck of a fired case. Also I'm as careful as I can be that bullet is straight in case when seating.

[knight0334]

I've seen that happen from the bolt of the gun slamming a cartridge that just didn't feed properly.

That exact thing happened on the very first cartridge I tried loading into my Stag M4. The cartridge didn't feed from the mag to the chamber properly, so the momentum of the bolt going home bent the cartridge and bulged out the shoulder exactly like that.

The ammo was factory cartridge and didn't have any imperfections when I loaded it in the mag.

[JoshIronshaft]

Talking to a very experienced reloader who I work with, he thinks this is due to thicker than normal brass cases, since I haven't seen this issue till now with no die adjustments, and that I should consider using a small base die to mitigate eliminate this issue. He used to see this issue infrequently before he switched to small base dies. Thoughts?

[JoshIronshaft]

Went through the last 30 cal can of 223 I loaded and found 6 of these buggers!



Varied head stamp.

I reset the bullet seating die and backed off the crimp die. I'm going to bust out a few hundred rounds and keep a closer eye on it.

I am fortunate to have access to machine guns every now and then and I store my ammo in bulk and just abuse it in general so I would like to keep the crimp.

What about the dillon tapered crimp die? Better solution?

[dkf]

Your probably hitting the brass on something either during bullet seating or crimping. As I said a collet crimp die like the FCD is not going to collapse the shoulder like that unless the die is hitting a part of the case. A heavy crimp with the FCD (when the die is set right) will actually deform the bullet without collapsing the case.

Is your bullet seating die capable of crimping too? If the die is set too low you could be collapsing the case with that.

[GeneCC]

This happened today, in my 16" barrel AR. The same thing happened in my 11.5" suppressed AR. They look identical. Both times the action was frozen out of battery and I had to "mortar" the rifle to open it (grab charging handle, slam stock against knee, inertia opens action) so it took some force.

You have a case gauge? I ask because I wonder if you have made the cases a bit too long for the headspace or the necks are too thick for the throat area of the chamber?

[dkf]

The rounds in post #14 don't need a case gage to see they fail. Inspect every round that comes off the press.

[Lycanthrope]

A small base die isn't going to fix that. That's being done on seating or crimping and I'll bet it's crimp. Are you sure your seater isn't crimping as well?

You also look like you're missing the cannelure and that's not helping. Did you short seat the bullets on those?


Lycanmicsomeformethrope

[Lycanthrope]

Look familiar?


http://www.brianenos.com/forums/inde...owtopic=140074


Lycanbadcolletthrope

[JoshIronshaft]

Those loaded rounds just barely fail to fully seat in my Dillon case gauge, they're not far off.

I reset my seating die to make sure it isn't crimping and I backed off the crimp die a touch. Following advice from THR I started seating the bullet deeper (within safe spec) to make sure I'm crimping on the cannelure. I'll run a couple hundred and watch for any more issues.