Leonardo da Vinci’s repeated-volley artillery design is commonly called the 33-barrel organ.
The machine arranged 33 small cannon barrels in three rows on a wheeled frame. The layout was intended to allow one row to fire while another cooled and a third was being loaded. This could produce more sustained fire than a single muzzle-loading cannon, at least in theory.
The nickname “organ” comes from the visual arrangement of the barrels, which resembles the pipes of a musical instrument. The weapon is also discussed as a type of organ gun or volley gun, but “33-barrel organ” is the specific name associated with Leonardo’s design.
Leonardo’s drawing demonstrates an attempt to solve a major artillery problem: slow reloading. It does not prove that the complete weapon was manufactured or successfully deployed. The concept influenced later interest in multi-barrel firearms, but it was not a modern machine gun.