And they want guns to appear realistic, so they tend to use real guns. Guns that make a big bang and a flash with lots of smoke and preferably with some (visible) recoil. All those objectives also could be met with a real gun that's been gimmicked so it can't fire a real bullet. Why they don't do this is God's own mystery.
Instead they use real guns that remain capable of firing a lethal projectile and then put them in the hands of actors who are unskilled in firearm safety. One would presume an industry that runs on the labors of limousine liberals is rife with individuals who think all guns are evil and so get apoplectic over the idea that they actually should learn something about them before using them on the set. Alec Baldwin obviously is the poster boy for this behavior since "Rust" would have made his eighth movie in which he used a firearm in his role, and he's still using them negligently.
So they use guns that look realistic because they are real, and they put them in the hands of actors who don't know Sweet Fanny Adams about firearm safety. What could possibly go wrong?
Their firewall against firearm misuse was supposed to be the studio's armorer, an ersatz firearms expert who is paid to coach the actors and assure that they only ever use the prop guns safely and responsibly. The military does something similar in its marksmanship training, and indeed at all live fire exercises. They have "Range Safety Officers" (RSOs) who control who can do what, and when. And it works well for the military but that's because on a military firing range, THE RSO IS GOD. His authority is not to be questioned and doing so will bring serious consequences.
And that's where Hollywoord is screwing the pooch. Their armorer has no real authority and is susceptible to the whims of both the actors and the studio. And the fickleness of both were in evidence in this tragedy because Baldwin erroneously believed the gun was loaded with a blank because he was told it was (neglecting to look for himself) and the studio had forbidden the armorer access to the set when the shooting occurred because of Covid restrictions.
Through negligent use of a firearm, Alec Baldwin killed a woman. But he only ever found himself in that predicament because the studio had allowed several potential single points of failure in a safety system that should have bad none. They allowed an actor to blow off firearm safety training from their professional expert and treated her like so much excess baggage when she should have been accorded the respect and the unquestioned authority of a Range Safety Officer.
Baldwin killed a woman, but he had help from the studio.
Alec Baldwin was "the studio". He was the producer.