What Leonardo da Vinci invention used several barrels arranged together to fire multiple shots?

Leonardo da Vinci's multiple-shot artillery design was a multi-barrel cannon.

Leonardo explored several rapid-fire weapon concepts, including a cannon with many small barrels arranged in parallel. The arrangement was intended to let one group fire while another was being loaded or cooled, potentially increasing the rate of fire compared with a single large cannon. Some versions were mounted on a wheeled frame for battlefield mobility.

The design is often described as an organ gun because the rows of barrels resemble the pipes of a musical organ. That nickname does not mean the weapon was musical; it refers to the visual arrangement of the tubes. Leonardo's drawings show military engineering aimed at reducing the delay between shots.

This weapon should not be confused with a machine gun in the modern sense. It still required manual loading and did not use cartridges, automatic cycling, or a continuous belt of ammunition. Its practical battlefield performance remains uncertain because the design was not a standard Leonardo-built weapon.