Isn’t it obvious that he is transferring guilt to the prop manager? His excuse, “I’ve never been handed a hot gun”, is the clue he is not accepting responsibility for the deadly act.
The “actor” who pulls the trigger is responsible for determining that the discharge is harmless. Failing to train actors using guns in the proper handling of firearms is a profound dereliction. Any “actor” using a gun with inadequate training in its proper use must be held fully responsible for its misuse.
“I’ve never been handed a hot gun”.
That line will get him the Oscar! (or thrown into prison for murder.)