How did the Gatling gun work before fully automatic machine guns were developed?

The Gatling gun was a hand-driven machine gun that functioned through a rotating cluster of barrels, typically numbering 6 or 10, mounted around a central axle.12

Operated by a hand crank, the weapon solved early issues of reliability and sustained fire by automating the loading and firing cycle. As the barrels revolved, each individual barrel underwent a specific sequence: it was loaded by gravity from a feed device, fired, and then went through unlocking, extracting, and ejecting the spent cartridge case during a single complete rotation.12

By utilizing the newly developed brass cartridge, which contained its own percussion cap, the Gatling gun allowed for rapid, continuous fire that was unmatched by other manual weapons of the era. While these guns were highly effective for their time, they were eventually rendered obsolete by the advent of smokeless gunpowder and the subsequent development of recoil- and gas-operated automatic weapons.1