I"m new to reloading, and noticed something yesterday. I bought a bag of mixed headstamp brass from the local gun show. Out of 100 cases I had 9 Federal cases and 4 of them got a bulge when I ran the expanding die. I also had 1 S&B case and 1 A-merc case do the same. Did I do something wrong by not checking length before expanding? The die felt tight going into all of these cases, like it was set to deep. On the previous case it was fine, everything is tight, and the following case would act normally. I expect to lose some brass to the gods, but the Fed cases seem to be a problem. Any have this happen or am I just doing something wrong?