The Machine Gun was a ballistic weapon and one of the War machines designed by Leonardo da Vinci. Originally intended for use by the Borgia forces, the 16th century machine gun was placed on a horse-drawn chariot, so that one could shoot at any targets that came within range. It was immensely powerful, slaying men and momentarily crippling horses with a single shot.
Around 1500, Leonardo was forced to create blueprints for a rapid-firing gun, and subsequently tasked his friend, the Assassin Ezio Auditore da Firenze with its destruction. After assassinating the overseer entrusted with its location, Ezio traveled to the Alban Hills] where he managed to remain undetected, before burning the blueprints for the device and setting off nearby barrels of gunpowder, destroying the main prototype.
After witnessing another horse-drawn prototype ride off in attempt to salvage the project, Ezio chased after the carriage on horseback, narrowly avoiding being gunned down by the weapon, before he hijacked the chariot it was mounted on and fended off numerous mounted arquebusiers.
After losing his pursuers, Ezio detached the prototype from the horses of the carriage and ignited the gunpowder laden chariot with his pistol. Because of this, the resulting explosion destroyed the machine gun, whilst Ezio rode to safety.
During Ezio's travels in Constantinople, machine guns were employed by both the Templars and Assassins during attacks on Assassin Dens. While the Templars made use of the machine guns by mounting them on war machines, the Assassins placed them on barricades. While both were equally effective against the enemy troops, they were less effective against structures or barricades that each side had constructed.
- Despite it needing a driver and a gunman, Ezio spent the first part of the escape steering the chariot, then later took over as gunman, much as he did with the Naval Cannon. However, this did not come without drawbacks, as the horses often sent Ezio crashing into buildings.
- When Ezio hijacks the chariot, he kills the gunman with his left Hidden Blade, and the driver with right, even if the player has not purchased the double blade.
- Successfully using and destroying the Machine Gun grants the player the "Bang!" achievement.
- Despite being called a machine gun, it fires in semi-automatic, rather than full-automatic. It is only a "machine" gun in the sense that one can fire several bullets at a time without having to reload.
- Leonardo's machine gun design in the game differs from the design he came up with in real life, which consisted of multiple barrels in one large rifle with a wheel, allowing the gun to fire several bullets at once, similar to the Maxim gun or a gatling gun.
- A miniature replica of the weapon can be found at the armory in Ezio's Hideout after completing the Outgunned memory.
- The memory description of "Outgunned" claims that the Machine Gun can kill one hundred men in mere seconds.