I volunteer at a Community Theatre in Florida where ,fortunately, the 'shooter' had bad aim. The facility was being used by a small seniors acting troupe. They were in tech rehearsal for 'Mice and Men' and the 'prop' pistol was brought in by one of the cast. Turns out it was a real pistol... Wouldn't even try to speculate 'HOW' this happens, but the Actor on the receiving end of the gun, lost some of his ear and most of his hearing in that ear. I think the policy at this particular theater is Balsa wood weapons!!

Real firearms do not belong on stage, ever.  End of discussion. 

You can get a prop for every type of firearm imaginable.  You can even get prop weapons that will go bang when you pull the trigger.  People can and have been killed by blanks.