http://en.wikipedia.org/wiki/Brandon_Lee#Death

> (...) behind schedule (...) they decided to make dummy cartridges from real cartridges by pulling out the bullets, dumping out the propellant and reinserting the bullets. However, the team neglected to remove the primers, which, if fired, could still produce just enough force to push the bullet out of the cartridge and into the barrel. At some point prior to the fatal scene, the live primer in one of the improperly constructed dummy rounds was discharged by an unknown person while in the pistol, leaving the bullet stuck in the barrel.

> (...) the same gun was later reloaded with blank cartridges and used in the scene in which Lee was shot. When the first blank cartridge was fired, the stuck bullet was propelled out of the barrel and struck Lee in the abdomen, lodging in his spine.