I went shooting with a friend last week who was running factory Armscor 9mm ammo. There were a couple times where he had a failure to feed; I didn't think much of it at the time and chalked it up to "the gun didn't like the ammo". However, today while I was reloading some of the Armscor brass from that outing (headstamp is "A USA") I discovered a case that had not been flared enough to accept a boolit. I measured the case length at 0.717". Seeing as the SAAMI minimum case length for 9mm is 0.744" I find this to be pretty severe. I have loaded about 50 of these cases and only found one like this so far.
Has anyone else come across this?
Edit: I like the 9x18 makarov explanation