Great question. The weapon that killed Brandon Lee wasn't a livee round, but a dummy round (no powder propellant) with a live primer cap. They use these to make it look like a revolver or magazine have a live rounds are there. When they pulled the trigger, the primer cap had enough propellant to dislodge the projectile into the barrel. When they changed to blanks for effect, the blank had enough propellant to fire the projectile into Lee, killing him. This is 100% negligence having live ammo at, near or even the same proximity of the set.