What weapon did Leonardo da Vinci design with three barrels arranged together for repeated firing?

Leonardo da Vinci designed a triple-barrel cannon with three barrels arranged together for repeated firing.

The concept used several gun barrels mounted on a frame so that one group could be fired while another was prepared. Leonardo’s aim was to improve the rate of fire of artillery, whose crews normally had to load, aim, and fire individual weapons in sequence. The arrangement could also help maintain pressure on an opponent during a battle.

This design should not be called a modern machine gun. It lacked automatic loading, metallic cartridges, and the continuous firing system associated with later firearms. It was a Renaissance volley weapon concept, dependent on black powder, separate projectiles, and human crews.

Leonardo’s military notebooks contain many studies of artillery, fortifications, and battlefield logistics. Like several of his weapons, the triple-barrel design is best understood as an engineering proposal rather than a weapon with a documented combat career.