What Leonardo da Vinci mechanism used a toothed drum to produce repeated rifle fire?

Leonardo da Vinci’s multi-barrel gun used multiple gun barrels arranged on a rotating frame to produce repeated fire.

The design, commonly known as Leonardo’s machine gun, placed a row or group of small cannons on a platform. A toothed-wheel mechanism could rotate the assembly, allowing one set of barrels to be fired while another was loaded or cooled. The arrangement was intended to increase the rate of fire against infantry.

It was not a modern machine gun. Leonardo’s weapon relied on muzzle-loaded gunpowder weapons, which required manual loading and had major limits in speed, accuracy, and reliability. The design also created logistical problems because many barrels and large quantities of powder would be needed.

Leonardo’s military notebooks contain many proposals for fortifications, artillery, and battlefield machines. The multi-barrel gun is notable for applying continuous rotation and repeated firing to an early firearm system.