In 1976, the Coast Guard cutter I was stationed on had a old 3" 50 gun mount. They had quit making the shells decades earlier. These were pre- WW2 guns.
We had gunnery practice every other patrol either shooting at a floating balloon or bombarding a deserted island way down the Aleutian chain. The solid brass empties were highly sought after.
Part way through my tour of duty on board we held practice at the deserted island. The first shell did not fire due to the breech not closed all the way. The gunners mate in a act we will never know why, used his shoulder to close the breech not knowing that the port elevation guy was pulling the trigger. The gun went off and threw him about 30 feet back near the superstructure. He suffered a concussion, cracked ribs, broken collarbone and possible internal injuries.
The GM was airlifted to Elmendorf and we never saw him again. As for the gun, the Coast Guard put out a directive and they were never fired again.