[Jaysun]

That's not good. Don't try to shoot it until is locks with the hammer down. The revolver cylinder should roll freely ONLY on the half-cocked position.

I read about that as one way to identify a revolver as an Iver Johnson that dates around 1900. There's no mechanism to hold the cylinder in place until the gun is cocked. Then the top of the trigger moves into one of the small slits on the cylinder and that's what holds it in place.

[Swordmaker]

HMMMMMM... I don't recall that.. but then I really wasn't too interested in Iver Johnsons. Looking at the cylinder I see normal locking slots for the cylinder lock snap and I fail to see why they would drop a proven technology in favor of a possible haphazard locking method at the time most dangerous... when the gun is discharging.

It may be that the model 1900's early model had a weak lock snap and it is often broken on those early models.