Yes he should. It might be more nebulous if another newer actor was handed the gun that killed but he’s a seasoned actor who had outsized clout and hiring/firing power on the show. There is no way he wouldn’t have been introduced to these concepts from other shows… so receiving a weapon from the first AD is damning.

Those firearm training session- s are an every production kind of deal for anyone who handles a live weapon. That means if you are seasoned you’ ve had this drilled into your skull. It establishes a chain of liability. The armourer is liable to follow and enforce the rules, the actor is liable in following the rules and reporting infringement of the rules as a condition of their participation, the 1st AD is liable for enforcing the safety rules on the set and addressing the concerns of the crew, the director is liable if they disregard the 1st AD’s veto of an action as unsafe and the production is liable if a producer or production manager is made aware of these safety checks being disregarded because they have firing power and an unsafe crew member in any of these positions is a danger to everyone on the set.

So frankly, they were treating live weapons as toys in an industry where the standard should be that even bouncy fake rubber replica guns get treated with the full respect afforded a dangerous weapon because you don’t fuck with guns on a set. -