They were new brass, first firing, brass and bullets sourced from ammo supply wharehouse, shot from pistol, RIA chamber.
I wasn't aware of issue with bad batch of brass, but this may be the case for me.
It has been too long a time since I bought the brass, and unless they are aware of the problem, and will exchange the brass, I guess they are a one shot thing.
I'm aware I can cut down 223 cases with a jig and resize, but I don't really want to invest the time into doing it. I have a friend that makes 300 blackout cases, so I'm familiar with it.
(At least at this point)
they were loaded 10 gr H110, full length sized, 40 gr armscor projectiles, small pistol primers and passed the plunk test, in the chamber.
If it were just to anneal the cases of a TCM, it would not be worthwhile, but I load 6 other rifle calibers. And of those the 6 mm rem is the hardest on brass but I run a max load in it.
So annealling is not out of the question for me to consider at some point.
I agree that as short as the case is, there is not a whole lot of space between the neck,/shoulder and the case web. So it brings up concerns other calibers don't have.
thanks for the info on batch of bad brass, that seems to make the most sense, hopefully they have it squared away now, if not, I'll make my own.