Well, we'll see what comes out of the trial. I don't have any knowledge of protocols to follow in movie production, so I have no particular claim about it.
I just find it strange that when an actor is handed an accessory, he should be responsible about this accessory. Like if he has to drive a car, he should be responsible if breaks eventually don't work.
The example you give probably makes sense. However, in this case it was not 'his' gun.