The actor you’re thinking of is Jon-Erik Hexum odf the 80’s TV-shows “Voyagers”.
From IMBD:
“However, on October 12th, 1984 after a long and draining day’s shooting on the set of Cover Up (1984) (TV), Hexum became bored with the extensive delays and jokingly put a prop .44 magnum revolver to his temple and pulled the trigger. The gun fired, and the wadding from the blank cartridge shattered his skull, whereupon the mortally injured Hexum was rushed via ambulance to hospital to undergo extensive surgery. Despite five hours of work, the chief surgeon Dr David Ditsworth, described the damage to Hexum’s brain as life ending, and one week later on October 18th, he was taken off life support and pronounced dead. However, Hexum’s commitment to organ donation, meant five other lives were assisted or saved with organs harvested from him. The youthful & charming Hexum was dead at only 26 years of age.”
Yup, That him.
I remember that show, It was one of the first “Flashy” cop shows that we’ve been subjected to ever since.