I got to work with a pair of Lorenzoni-Berselli pistols not too long ago. Let me see if I can recall this correctly. The "wheel" or "drum" at the breech has two chambers that pick up powder and the ball from separate "magazines" on the left side of the gun. You aim the gun towards the ground since the ball and powder simply used gravity to feed into the chambers and rotate the "crank" lever forward and then backward. When you are cracking forward, a ball is loaded in the chamber from the wheel at the breech, and when you pull it back towards you, powder that was picked up by the second chamber as you rotated it forward is dropping in behind the ball. The pan is also primed and the hammer is cocked as you pulled the crank back. The fit of all the parts had to be very tight to ensure hot gas did not leak back into the powder reservoir and turn the gun into a grenade. Regardless of how well things fit, I don't think I would have felt remotely safe shooting one. They would have fired much faster than anything else available at the time and some could hold quite a few shots. The American Cookson repeaters used the same basic idea.
