What Leonardo da Vinci machine used multiple barrels to fire repeated volleys?

Leonardo da Vinci’s 33-barrel organ was a multi-barrel gun designed to fire repeated volleys.

The weapon arranged 33 small guns in three rows on a wheeled frame. The name “organ” refers to the visual similarity between the parallel barrels and the pipes of a musical organ. The arrangement was intended to allow one row to fire while another was being loaded or cooled, improving the rhythm of battlefield use.

It is often called a machine gun in popular accounts, but that description can be misleading. Leonardo’s device was not an automatic firearm: each barrel still required separate loading and ignition, and there is no evidence that the complete weapon was built or used in battle. Its important innovation was the organization of multiple barrels to produce concentrated, repeated fire.