The Puteaux SA 18 is a French single-shot, breech-loading cannon, used throughout the World Wars, primarily mounted on combat vehicles. The gun was designed in 1917 and manufactured by the Atelier de Construction de Puteaux. It has a calibre of 37mm and uses a semi-automatic breech system that allows for a high rate of fire of 15 rounds per minute. The gun is operated by one soldier since it is so easy to use, with a low incidence of jamming. Puteaux cannons were primarily intended to be used against infantry and machine-gun nests, as its low muzzle velocity of 600 m/s make it unsuitable for anti-armour use. Nevertheless, its users were issued armour piercing 37×94 mmR ammunition as late as 1940. Its most famous use is in the Renault FT light tank, though it was also seen two decades later in the fields of Alsace-Lorraine.
