Leonardo da Vinci’s multi-barrel cannon design contained 33 barrels.
Leonardo’s drawing shows three rows of 11 small cannon barrels mounted on a wheeled frame. The arrangement was intended to fire a concentrated volley and then be rotated or replaced while another loaded frame was prepared. This made the design an early attempt to improve sustained battlefield firepower.
The weapon is commonly called a 33-barrel organ, organ gun, or volley gun because its parallel barrels resemble the pipes of a musical organ. It should not be confused with a modern machine gun: the barrels were separate guns, and the design still depended on manual loading and ignition.
Leonardo’s military notebooks contain many proposed weapons, including artillery, bridges, and armored vehicles. His drawings reveal engineering ideas, but there is no firm evidence that every weapon he sketched was built or used in combat.