What repeating firing mechanism did Leonardo da Vinci sketch for a multi-barrel gun?

Leonardo da Vinci sketched a 33-barrel organ as a multi-barrel gun. The design arranged 33 small guns in three rows on a wheeled frame, allowing one row to fire while the others were loaded or cooled.

The nickname “organ” comes from the visual resemblance between the parallel barrels and the pipes of a musical organ. Leonardo’s arrangement sought to increase the rate of fire compared with a single muzzle-loading gun, while the carriage made it possible to move the weapon.

The weapon was not a true machine gun in the modern sense. It still required separate loading and firing operations, and its practical battlefield performance is uncertain. Leonardo’s sketch belongs to his broader work on military engineering, where he explored artillery, fortifications, bridges, and armored vehicles.