I'm passing on this error of mine in the hopes it'll save someone else some grief.
I was at the range with Bersa .380 and all went well with the first two mags. I loaded up the third and when I inserted the mag and releases the slide, I couldn't fire the weapon. Worse, the slide couldn't move, it was stuck solid. I ended up having to take it to a gunsmith who was able to extract the stuck round.
I couldn't figure out the problem until I got home and measured the case O.D. It turns out I had never sized or de-capped the case, I merely flared the case, charged it, and seated the bullet. Since the case was expended from firing it ended up getting stuck in the chamber and since it contained a spent primer it wouldn't fire.
So I guess I'll have to inspect every case before I charge it.
GH1