What Leonardo da Vinci design is often described as an early version of a machine gun?

Leonardo da Vinci’s 33-barrel organ is often described as an early machine-gun concept.

The design consisted of 33 small cannons arranged in three rows on a triangular frame. The rows could be fired in sequence, allowing one group to cool while another was being loaded. Its name comes from the visual resemblance to a musical organ rather than from any musical function.

Leonardo proposed the weapon for battlefield use in the late fifteenth century. It was intended to increase the rate of fire compared with individual muzzle-loading guns, although it still required manual loading and did not fire continuously like a modern machine gun.

Calling it a machine gun is therefore a comparison, not a claim that it used modern automatic operation. Leonardo’s design belongs to the transitional history of artillery, where engineers sought faster loading, better organization, and greater concentration of fire.