Home > Hispano 20mm cannon

The cannon was based on the earlier Swiss Oerlikon HS.7/HS.9 weapons, which Hispano Suiza manufactured under license. In the late 1930s engineer Mark Birkgit designed a new and much improved version with a revised action, faster rate of fire, and higher muzzle velocity. This entered service as the HS Type 404. This was adopted by the RAF and FAA in 1941 as the Hispano Mk II and by the U.S. as the M1 and incrementally improved M2 (although American-made weapons had minor production differences that made them notably less reliable than their British counterparts). It was primarily used by the U.S. Navy. The British upgraded to the Mk V, which was lighter and had a higher rate of fire, and the U.S. followed suit with the M3. After World War Two the USAF adopted a version of the M3 cannon as the M24, similar in most respects except for the use of electrically primed ammunition.

The Hispano fired a 130-gram (4.59 oz) 20mm x 110mm projectile with a muzzle velocity between 840 m/s (2,755 ft/s) and 880 m/s (2,888 ft/s), depending on barrel length. Rate of fire was between 600 and 850 rounds per minute. It was 2.36 m (7 ft 9 in) long, weighing between 42 kg (93 lb) and 50 kg (110 lb). The British Mk V and American M3/M24 weapons were lighter with higher rates of fire than the early HS 404 guns.

The U.S. Navy later replaced the M3 with the Colt Mk 12 cannon, while the British RAF and FAA went to the 30mm ADEN cannon. The USAF adopted the M39The Pontiac M39 was a 20 mm revolver cannon developed for the United States Air Force in the late 1940s. It was used on a number of fighter aircraft from the early 1950s through the 1970s. The M39 was developed by the Springfield Armory, based on the Worl revolver cannonA revolver cannon is a type of autocannon. It uses a cylinder (like that of a revolver) with multiple chambers to speed up the loading-firing-ejection cycle. It differs from a Gatling gun in having only a single barrel. Revolver cannons were invented by M to replace the M24.