Ok, this is a sketch for an old school revolver, based on the Colt 1851 Navy Percussion pistol. The idea behind this is:
One: to be the pistol of a very rich, very connected, and very intelligent bandit/thief in a renaissance era world where firearms are really just coming into being. (i know that this pistol is from an era roughly two hundred years after the introduction of the gun to europe, the idea is that it's a one of a kind work of genius)
Two: It's internal workings are mostly gears, you crank the knob on the outside to cycle the chamber for the first bullet to be fired, after that the recoil drives a grooved metal rod backwards that turns an internal gear that in turn cranks the visible gear on the outside to cycle the next bullet in the chamber.