Just my two cents, and I absolutely am not pretending to have any experience with this. I’d assume so long as the actor isn’t negligent or grossly irresponsible they’re in the clear. Actors are not firearms experts, and training every actor to be Keanu Reeves/John Wick is super expensive. So whomever is the firearms expert, and whomever was involved with the contracting of that expert face liability.

That’s why Baldwin the actor isn’t responsible, but Baldwin as producer might be. Since as a producer he’d bear responsibility for hiring and contracting.