TexasCHLforum.com

Looks like some 9mm cases my daughter and I "enjoyed". A couple of times in an old Star M30 I use to have and one in my Shield. No damage to either gun but we had to fight flinching for a bit afterwards. I know there were no double, or over charges for that matter, due to using a single stage press and the way I charge the cases. (Put 50 primed cases in a loading block, charge, then look at the cases. Any difference in powder level is very easy to spot.)
Since it happened in two different guns all that was left was weak cases. These had been reloaded several times and I'd guess were at least 10 years old. I figured the brass was just fatigued beyond use. Did go on and shot them up. Not the smartest thing to do but also didn't bother picking up brass afterwards.