Letting go of a hammer will only discharge very old historical single action revolvers. All modern revolvers and semi automatics have firing pin safety mechanisms designed specifically to prevent this problem. I have two 1865 revolvers both will fire from half cocked if you don’t seat the hammer back on the sear. The 1911 is also.single action and you can drop the hammer from half cock nothing will happen why? Because unless the side safety is down,the rear grip safty is fully depress and the trigger is back the firing pin is out of line with the primer. Same for a Sig P226 take it to just under half cock let the hammer go click nothing. Do that with a pre 1870 revolver and they will.go bang.
The gun in this case is a replica of a 1869s era revolver it comes in two versions one is modern with a transfer bar safety the other is historically accurate version with a always live firing pin I think we just found out what version was on set. If you pull the hammer back on the original and lose your grip before that hammer clicks back and locks on its sear it will fly back.forward with full speed of the spring tension you just pull it too and nearly every time light off the round in the cylinder under it which also would rotate back to it’s original position as the spring unwound there is no back catch paw or rachet on those older guns at half.rock the chamber will index forwards manually but will rotate back if you let the hammer go.
I’ve read elsewhere that this particular replica gun DID have a transfer bar, so it could ONLY fire if the trigger was pulled. Of course, just because I read it doesn’t make it so. But it would take the cops about 2 seconds to figure it out...