Nope. Not possible.
I have a single action Colt revolver model 1851. Dropping the hammer on a live round is not possible because the cylinder will not be perfectly aligned. A partially cocked hammer, that is prematurely released, will NOT hit the cap or primer, which ever the case may be. Plus my Colt has a half cocked position that locks the gun up. Bottom line is the hammer has to go all the back to turn the cylinder completely into proper position. Then the only way to release the hammer is to pull the trigger. He is BS’ing.
Yes, old Colts do have a "hair" trigger.
PS: This saying "Don't go off half-cocked” means don't go off with a gun that WON'T shoot, meaning don't go off unprepared.
Well watch the video. It came out last night. Baldwin says this is exactly what happened. He let slip the hammer. They teased us with the “I didn’t pull the trigger” headline.