Just a possibility,
Oncce upon a time I was trying to call coyotes. No luck and no luck and no luck.
After about 6 stands, unloading and loading every time with an ar-15, same shell every time, The last time I unloaded I found the bullet setback into the case enough that the bullet ogive was almost into the case shoulder, almost rattling in the case.
I never shot that one but often thought that it could have been a catastrophic event. No way we'll ever know but it would have been hard to diagnose for me.
Now I crimp my 223 better.
I’ve never crimped my .233/5.56 ammo and never had a problem…however…about 15 years ago my local Walmart hadn’t been having much luck moving Remington.233 ammo loaded with 50 grain HP’s. Finally, they marked it down to $5.00/box and I took all they had at that price, for the brass if nothing else. Figured I’d shoot it up for fun… To get an idea of how accurate the stuff was, (it wasn’t btw) I tried it in my Les Baer Super Varmint. After four or five shots, for some reason I ejected an unfired case and did a double take: the bullet was crammed significantly into the case neck, enough so to scare the hell out of me. I shot up the rest of them in a bolt gun. I have never had a problem with any other ammo that way (and still don’t crimp stuff for my AR’s. I suspect that some bullet profiles and some feed ramp configurations don’t play well together.
