What did Leonardo da Vinci design with 33 small-caliber gun barrels arranged in a row?

Leonardo da Vinci designed a 33-barrelled organ with 33 small-caliber gun barrels arranged in a row.

The weapon is commonly called a “33-barrelled organ” because its grouped barrels resembled the pipes of a musical organ. Leonardo’s concept placed the barrels on a frame so that several shots could be fired in sequence or in a coordinated volley. The arrangement was intended to improve the speed and continuity of fire compared with a single cannon.

The design belongs to Leonardo’s military studies, which included fortified positions, bridges, armored vehicles, and artillery. It was not a modern machine gun: the barrels still required loading and firing, and the weapon depended on black powder technology.

Popular descriptions sometimes call the device a “machine gun,” but that label can create a misleading impression. Leonardo’s proposal was a multi-barrel gun meant to deliver repeated fire, not a self-loading firearm. The surviving drawings are evidence of the concept, not proof that Leonardo’s exact version entered military service.