We had one in basic in the Army, but only a blank. I was not involved. It was while turning in our rifles after coming back from the range. You are never supposed to leave the range with ammo (even blanks) or brass. I don't know what happened to the individual, but it was not handled lightly. Apparently, someone left the range with a blank (I hope it was a blank) in his rifle, and discharged it horsing around on line at the arms room.
Ah ... the memories.
When I was in Basic a half-century ago, we had a Corporal who was in charge of the arms room. He was an E-4 which is not a high rank but he out-ranked all of us E-1 recruits by the equivalent of three stripes.
The job of checking in rifles is very painstaking because the rifles all have to be checked to make sure they are cleared, cleaned, properly assembled, and that the serial number is properly accounted for. As a result, there is plenty of time for horsing around by an entire company of recruits standing in line.
The Corporal thought it was his job to maintain order (which it was) and he would consistently give people a hard time. One day he pointed a bayonet at a member of my platoon while giving him some order. The guy in my platoon drew his bayonet, attached it to his rifle, assumed an attacking stance, and yelled "HA".
He then told the Corporal, "You want to play f..k around, I'll play f..k around!" (This was at a time when there were quite a few unhappy draftees in our Basic Training company.)
The Corporal turned white as a sheet and I never heard him say another word. Since he was the one who initially pointed a bayonet and was at fault, he couldn't report the incident. He left everybody alone after that.