I forget the name of the actor but a number of years ago he was killed by a blank in a .44 magnum. The concussion hit his head & caused fatal brain damage.
Bruce Lee also...
And his son?
Black powder. Makes smoke for effect as well
I believe Bruce Lee's son was killed when someone loaded live ammo instead of blanks or switched a gun...something like that. At any rate, he was killed by a bullet, not the concussive shock from a blank.
I thought it was more that someone loaded dummy rounds for a scene. They then unloaded the dummy rounds and loaded blanks for the shootout. The problem was that one of the dummy rounds had broken, causing the bullet to come loose from the casing and remain in the chamber. the gun expert missed it, and when the blank fired, it provided enough power to propel the bullet.