Rheinmetall 120 Mm Gun - Background

Background

Worried about the inability of the 105-millimeter (4.1 in) L7 tank gun then in use across NATO forces to penetrate new Soviet armor, Rheinmetall began development of a new tank gun in 1965. The first instance of a larger Soviet tank gun was witnessed on the chassis of a modified T-55 in 1961. In 1965, the Soviet Union's T-62 made its first public appearance, armed with a 115-millimeter (4.5 in) smoothbore tank gun. The Soviet decision to increase the power of its tank's main armament had come when, in the early 1960s, an Iranian tank commander defected over the Soviet border in a brand-new M60 Patton tank, which was armed with the British Royal Ordnance L7. Despite the introduction of the T-62, in 1969 their T-64 tank was rearmed with a new 125-millimeter (4.9 in) tank gun, while in 1972 Nizhny Tagil began production of the T-72 tank, also armed with the 125-millimeter (4.9 in) gun. For example, at the fighting at Sultan Yakoub, during the 1982 Lebanon War, the Israeli government claimed to have destroyed nine Syrian T-72s with the Merkava main battle tank, armed with an Israeli production version of the American M68 105-millimeter (4.1 in) tank gun (which in turn was based on the British L7). Whether or not true, the Soviets test-fired a number of Israeli M111 Hetz armor-piercing discarding sabot rounds at Kubinka, finding the 105-millimeter (4.1 in) round was able to perforate the T-72's sloped front section plate but not its turret armor. In response, the Soviets developed the T-72M1. This led Israel to opt for a 120 mm tank gun during the development process of the Merkava III main battle tank. This case is similar to the American decision to replace the M68 105-millimeter (4.1 in) tank gun with Rheinmetall's 120 mm gun in 1976; the introduction of the T-64A had raised the question within the armor community whether the new ammunition for the existing gun caliber could effectively deal with the new Soviet tank.

In 1963 Germany and the United States had already embarked on a joint tank program, known as the MBT-70. The new tank carried a three-man crew, with the driver in the turret, an automatic loader for the main gun, a 20-millimeter (0.79 in) autocannon as secondary armament, an active hydropneumatic suspension and spaced armor on the glacis plate and the front turret. The new tank concept also had improved armament, a 152-millimeter (6.0 in) missile-launching main gun, designed to fire the MGM-51 Shillelagh anti-tank missile. However, the German Army was interested in a tank gun which could fire conventional ammunition. Although there were attempts to modify the 152-millimeter (6.0 in) tank gun to do so, the process proved extremely difficult, and the Germans began development of the future Rheinmetall 120 mm gun instead.

In 1967 the German Ministry of Defense decided to re-open a Leopard 1 improvement program, known as the Vergoldeter Leopard ("Gilded Leopard"), later renamed the Keiler ("Wild Boar"). Krauss-Maffei was chosen as the contractor, and two prototypes were developed in 1969 and 1970. This program grew into the Leopard 2; the first prototype of the new tank was delivered in 1972, equipped with a 105-millimeter (4.1 in) smoothbore main gun. Between 1972 and 1975 a total of 17 prototypes were developed. The new 120 mm gun's ten-year development effort, which had begun in 1964, ended in 1974. Ten of the 17 turrets built were equipped with the 105 mm smoothbore gun, and the other seven were equipped with the larger 120 mm gun. Another program aimed to mount the 152-millimeter (6.0 in) missile-gun was also developed in an attempt to save components from the MBT-70, but in 1971 the program was ended for economic reasons. Instead, the Germans opted for Rheinmetall's 120 mm L/44 smoothbore tank gun.