Double action, pre Civil War design percussion revolver. It has a fully enclosed cylinder, i.e. a top strap. What I don’t get at the moment is why there are twice as many cylinder notches as there are chambers.
This is the sort of thing I’d like to own, and yet I can give no practical reason for it whatsoever.
ETA; I think I figured out the cylinder notch thing. It must be a safety system. Colt’s, Remington and others had similar features, pins or notches in the back of the cylinder to engage the hammer, that more or less locked the cylinder half way between chambers, so the hammer could rest safely between chambers, allowing the carrier to have all chambers loaded rather than resting the hammer on an empty chamber. This revolver is simply using the existing bolt (cylinder lock) for that purpose, methinks, hence the “in between” cylinder notches.