It sounds like normally there’s some hand-holding with the actors, but at least when an actor is handed a gun, he’s supposed to see what’s (not) in it. And he’s not supposed to hold the firearm between takes, let alone point it at someone and place his finger on the trigger, which Baldwin clearly did.
Discussion
Lemme see if I can find any bts videos for you of non Baldwins talking about guns on set
https://youtube.com/shorts/UELwDUEl1Po?si=GqfQN9JYMJyyEQRO
https://youtu.be/yMgCDrgTrgM?si=S9BRoSaI0QbJJwdh
https://youtu.be/EjpKAysj0JM?si=wfwkEjKpVGYhu5-w
If you're only going to watch 1
Watch the will Smith one then realize it's a joke and watch the Clooney one but fast forward to like a third to half of the way in
I watched all of them. (I did skip over what I think were introductory remarks by John Schneider.) So I see there is a protocol (i.e., a set of habits) for handling firearms on set. At the very least, the armorer who handed the gun to the assistant director should have verified the gun was empty, and then the AD should also have done the same. Three of the videos made it sound as though the AD should have proved to Baldwin that the gun was empty, before handing it to him. The last video was ambiguous on that point. Either way, Baldwin is in trouble because he was a producer, and his set deviated from standard practices.