Rheinmetall 120 Mm Gun

The Rheinmetall 120 mm gun is a smoothbore tank gun designed and produced by the West German Rheinmetall-DeTec AG company, developed in response to Soviet advances in armor technology and development of new armored threats. Production began in 1974, with the first version of the gun, known as the L/44 as it was 44 calibers long, used on the German Leopard 2 tank and soon produced under license for the American M1A1 Abrams and other tanks. The American version, the M256, uses a coil spring recoil system instead of a hydraulic system. The gun has also been exported to South Korea and Japan for their indigenous tank designs, as well as other nations that have procured the Leopard 2 and the M1 Abrams. The 120-millimeter (4.7 in) gun has a length of 5.28 meters (17.3 ft), and the gun system weighs approximately 3,317 kilograms (7,310 lb).

By 1990 the L/44 was not considered powerful enough to deal with the future Soviet armor, which stimulated an effort by Rheinmetall to develop a better main armament. This first revolved around a 140-millimeter (5.5 in) tank gun named Neue Panzerkanone 140 ("new tank gun 140"), but later turned into a compromise which led to the development of an advanced 120 mm gun, the L/55, based on the same internal geometry as the L/44 and installed in the same breech and mount. The L/55 is 1.3 meters (4.3 ft) longer, giving an increased muzzle velocity to ammunition fired through it. As the L/55 retains the same barrel geometry, it can fire the same ammunition as the L/44.

This gun was retrofitted into German and Dutch Leopard 2s, and chosen as the main gun of the Spanish Leopard 2E, the Greek Leopard 2HEL, and South Korean K2 Black Panther battle tank. It has been tested on the British Challenger 2 as a potential replacement for its current weapon, the rifled L30 120 mm cannon.

A variety of ammunition has been developed for use by tanks with guns based on Rheinmetall's original L/44 design. This includes a series of kinetic energy penetrators, such as the American M829 series, and chemical energy anti-tank warheads. Recent ammunition includes a wide range of new anti-personnel rounds and demolition munitions, giving tanks armed with the L/44 and its derivatives greater versatility on the modern battlefield. The LAHAT, developed in Israel, is a gun-launched missile which has received interest from Germany and other Leopard 2 users, and is designed to defeat both land armor and combat helicopters. The Israelis also introduced a new anti-personnel munition which limits collateral damage by controlling the fragmentation of the projectile.