Should the guy who shot Brandon Lee have been tried and convicted of manslaughter?
Ok, did a quick wiki search of it
"In a film shoot prior to the fatal scene, the gun that was used as a prop (a real revolver) was loaded with improperly made dummy rounds, improvised from live cartridges that had the powder charges removed by the special effects crew, so in close-ups the revolver would show normal-looking ammunition. However, the crew neglected to remove the primers from the cartridges, and at some point before the fatal event, one of the rounds had been fired. Although there were no powder charges, the energy from the ignited primer was enough to separate the bullet from the casing and push it part-way into the gun barrel, where it got stuck—a dangerous condition known as a squib load".
Rule of thumb for a squib round is, of course keeping the gun pointed down range for about a minute or two in case the round the goes off.