Baldwin should have generally just kept his mouth shut. In his interview, he made claims about what happened that are wildly unlikely and which get tested here.
I have several single action revolvers, including two that are extremely similar to the Colt 1873 model being tested here, and I can tell you with a massive degree of certainty that Baldwin had to have had his finger squeezing the trigger for the gun to fire the way it fired.
I get that he was practicing the draw for camera, and that he was getting ready for the cameras to roll. The real problem -- as I've said repeatedly here -- is the plethora of failures by the 1st AD and the Armorer. But his claims about what happened are nonsense.
As Brandon Herrera explains in this video:
Just flicking the hammer a little bit isn't enough to set off the primer of a bullet.
Pulling the hammer back far enough to get to half-cock not only locks the hammer in a mid-position, you can't unlock it unless you pull it back a bit farther and depress the trigger, which is a thing you have to do very intentionally.
Half-cock also shifts the cylinder to an offset position so the primer isn't even in line with the firing pin. This is so you can't accidentally discharge the gun while loading.
Fully cocking the gun requires a trigger pull... or, again, an intentional return to its starting position by squeezing the trigger and letting it down gently.
The only way the gun was going to go off is if Baldwin somehow managed to take a sledgehammer to the back of the gun whacking the firing pin into a primer, or -- much more likely -- that he had the trigger pulled and "fanned" the hammer by accident.
In any case, there should never have been a live bullet on set... but jeez, man... don't blame the gun.