To work the gun, you switch a crank, which revolves the barrels inside the cylinder. Just about every barrel passes beneath an ammunition hopper, or carousel journal, as it reaches the very best from the cylinder. A new cartridge falls in to the breech as well as barrel is loaded. https://machguns.com/product/lot-1450-auto-ordnance-a-range-1928-thompson-class-iii-nfa/