Sure, it went off all by itself.
Typical, try to find a way to blame the weapon instead of the humans who made a bunch of bad decisions.
This is a single action revolver, you first have to manually cock the hammer to before it will shoot.
You can pull that trigger till the cows come home and it will never fire until after you cock it.
Something you never do until just before the moment you intend to shoot it, the trigger can be very touchy then with a pull weight between 2 & 5 lbs, what some would call a "hair trigger". It is a very dangerous condition and anyone who's handled guns knows that.
"Baldwin, 66, said he cocked the reproduction 1873 Single Action Army pistol before it fired a live round that killed the rising-star cinematographer and wounded director Joel Souza."
I'm not saying Baldwin is liable. Unless he intended to kill the victim and put the live round in the gun himself, he was only playing his part.
Just don't blame the gun for doing what it's designed to do, and never should have been there in the first place.