What Leonardo da Vinci artillery concept placed several guns on a rotating platform?

Leonardo da Vinci’s artillery concept that placed several guns on a rotating platform was the 33-barrel organ.

The design arranged 33 small cannons in three rows on a broad triangular frame. The frame could be rotated, allowing one row to fire while the other rows were being loaded or cooled. The arrangement explains the nickname “organ”: the parallel barrels resembled the pipes of a musical instrument.

Leonardo’s proposal addressed a serious limitation of early artillery. A conventional cannon had to be reloaded after each shot, while a battery of barrels could deliver a concentrated volley. The carriage was also designed to be mobile, making the weapon easier to reposition than a massive fixed bombard.

The 33-barrel organ is often loosely called a machine gun, but that modern label is misleading. It did not fire continuously from a single automatic mechanism. It was a manually loaded multi-barrel artillery system, and there is no firm evidence that Leonardo’s exact design was built and used in battle.