I collected up all the miscellaneous .45ACP cartridges on & around my friend's reloading bench a while back.
This morning I took those 31 rounds to the range & fired them off from the 1911 A1 I use for practical pistol competitions.
Had three that wouldn't light off despite good firing pin hits & the second from last won the prize.
HARD recoil, burning powder in my face & the magazine blown half out the pistol.
The magazine, a Chip McCormick Shooting Star is toast, with the body bowed, spring compressed to a third of normal & follower buckled.
After checking it over I fired another magazine full of my own reloads through the pistol to test function & it was fine.
At first I thought it was an out of battery issue but no, it happened when I pulled the trigger, so most likely a double charge.
Luckily for me, I wear glasses with protective lenses, so my eyes didn't get peppered & judging by the marks on my cheek it would have been serious.
No more unknown ammunition for me.