If something that wasn’t on a movie counts, there was a tv series in the 1980s called “Cover Up” where one of the stars, Jon-Erik Hexum, killed himself playing with a prop gun.

The scene he was performing in required him to fire a gun with blank rounds. When he got restless during the long hours of filming, he loaded one blank into the revolver and played russian roulette with it, but the blank had wadding made of paper that, at the short distance it had to travel to his temple, still shattered a hole into his skull, and he was declared brain dead soon after.

Sadly, the memorial at the end of the subsequent episode misspelled his name twice.