What rotating weapon did Leonardo da Vinci sketch with multiple gun barrels?

Leonardo da Vinci sketched a 33-barrel organ as a rotating weapon with multiple gun barrels.

The design arranged small cannon or firearm barrels on a wheeled frame in three rows of eleven. The frame could be turned so one row was aimed while another was loaded. The nickname “organ” comes from the visual resemblance between the parallel barrels and the pipes of a musical organ.

Leonardo's proposal addressed a practical problem of early firearms: loading and firing individual weapons was slow. A battery of barrels could deliver a concentrated volley, and a rotating arrangement could potentially improve the rhythm of firing. The design was still limited by the technology of gunpowder, barrel manufacture, recoil, and reloading.

It is often loosely called a machine gun, but that modern label can mislead. Leonardo's weapon was not an automatic firearm with a continuous feed; it was a manually operated multi-barrel gun. The drawing belongs to his broader studies of military engineering, which included fortifications, artillery, bridges, and defensive systems.