My take is that Alec Baldwin the Actor isn't to blame. Alec Baldwin the Producer caused all of the Armourer problems by running a low budget production.
As an actor he wasn't supposed to check the gun, however as a producer he failed by not hiring the correct licensed armourer due to cutting corners.
Checking a revolver to confirm they type of prop ammo is very different than a regular weapon check.
Different shots require different ammo. You may have a shot where the revolver is seen from the business end, so there needs to be a bullet of some kind in the cartridge - so maybe it's a real bullet with no powder or primer. Or maybe the shot shows an open cylinder, so you need primers but no bullets. Or maybe you need to show the actor loading, so it's a plastic primer or entirely fake round. Or maybe it's being fired, so you need a blank...
The mixture of different kinds of prop ammo is how Brandon Lee was killed on set. A bullet came dislodged from a round being used for a previous scene and was still in the barrel when a blank was fired. That effectively made a live round that killed Lee.
So the barrel also needs to be checked for squibs if it's goong to be loaded with blanks.
It's not as simple as a regular press-check or opening the cylinder. I carry a gun every day and am a firm believer in gun safety at all times, but props are treated differently because they are different.
As a part of their job, actors will point guns at each other and pull the triggers. The normal firearm safety procedures just don't work with them.
Especially aiming directly at her and pulling the trigger. I don't believe it was malicious but damn; I would never consider that without triple clearing the weapon. I still would feel comfortable.
Even if he took the bullet out he would have seen it was indeed a blank. He would have had to take the bullet out and hold the barrel up to the light with the chamber open to see a previous bullet was stuck in the barrel.
That really depends on what kind of producer he was. Many times getting a producer credit just means you're a major stakeholder or own some rights involved in the project. A producer isn't a blame magnet, and negligence can be proven at a level lower than a producer.
As a human, if you are handed a gun, you check to see if it's loaded and what it's loader with. That is the first thing you do when handed a gun. Anything else is irresponsible.
But... What if I'm an actor who's never seen a gun.. Do i quit or is it too much of an expectation for an expert to be present and why the hell would that gun be real to begin with?
"Wait, so what do I need to do to uncock it so that I can check it over?"
"Actually, it's weird. You need to pull the trigger halfway, and it releases. But do it carefully."
"...uh..."
"Okay, after nearly shooting my foot off, I've opened the gun, and there appear to be rounds inside!! Stop the shoot!"
"Oh. Those are blanks."
"Wait, how do I know they're blanks?"
"Same way you know how to uncock it."
He pulled a Boeing max basically. Where in they refused to pay for pilot training which led to many deaths until someone was convicted and they were forced to pay for pilot training. Cutting corners shouldn’t come at a cost of complete negligence for human life.