The procedure for changing the watch involved handing over the gun and holster. The guy going off watch would draw, rack the gun, point it in a safe direction and pull the trigger. Since everyone was used to carrying it empty, few really checked the chamber.
So they did that and two guys neglected to remove the magazine beforehand. *Bang* Each time, the ship was outboard of a certain destroyer tender, at different times. Each time, the round hit the tender.
Both times, the sailor involved was from the same division. During a later tender availability, at the opening conference, the division officer presented the officers from the tender with a plaque that had a Purple Heart with an Oak Leaf Cluster and the dates of the NDs. Everyone thought it was funny as hell, except for the tender's new CO, who looked at his XO and muttered: "You're gonna brief be about this afterwards, aren't you, XO."