Royal Ordnance L7


The Royal Ordnance L7, officially designated Gun, 105 mm, Tank, L7, is the basic model of the United Kingdom's most successful tank gun. It is a 105 mm L/52 rifled design by the Royal Ordnance Factories, intended for use in armoured fighting vehicles, replacing the older QF 20-pounder gun mounted on the British Centurion tank. The successful L7 gun has been fitted on many armoured vehicles, including the Centurion, the German Leopard 1 and, in an altered design, as the M68 gun in several variants of the US M48 Patton and M60.
The L7 is a popular weapon and continued in use even after it was superseded by the L11 series 120 mm rifled tank gun, for some Centurion tanks operating as Artillery Forward Observation and Armoured Vehicle, Royal Engineers vehicles. The L7, and adaptations of it, can be found as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War.

History

Both the United Kingdom and the United States had been developing projects for high calibre guns during WWII in order to compete with increasingly heavily armoured German tanks, and later for Cold War Soviet tanks. The US developed several heavy tank designs during this period, notable were the US 105 mm gun motor carriage T95 as well as the QF 32-pounder mounted on the British A39 Tortoise heavy assault tank.
The US foresaw difficulties in engagements against the Soviet IS-3 and 4 with its M47 Patton. This led to the introduction of the M103, a heavy tank designed to counter Soviet heavy tanks. It mounted an extremely powerful 120 mm cannon but the ammunition was so large that it required two loaders, one for the shell and another for the separate propellant charge. Of the 300 M103s built, most went to the Marines. The UK came to the same conclusions and developed their own heavy tank, the Conqueror, which mounted the L1 120 mm gun.

United Kingdom

During the Hungarian Revolution of 1956, a Soviet T-54A medium tank was driven onto the grounds of the British embassy in Budapest by the Hungarians in November. After a brief examination of this tank's armour and 100 mm gun, British officials decided that the 20-pounder was apparently incapable of defeating its frontal armour. This meant the most common British tanks were no longer able to effectively deal with Soviet medium tank designs, let alone their heavy tanks.
These events spurred the United Kingdom to employ a new high-velocity tank gun in 1958, the Royal Ordnance L7 to keep existing Centurion tanks viable against this new Soviet tank design. While the United States began design development of the XM60 tank in 1957 and began user trials of the weapon in 1958. The L7 was specifically designed to fit into the turret mountings of the 20 pounder. This would enable the Centurion tanks to be up-gunned with minimum modifications; hence, the fleet could be upgraded in a shorter time and at a lower cost. The first production tank to integrate the L7 was a single up-armoured Centurion Mark 7 in 1958 which was to prove the future viability of up-armouring and up-gunning the Centurion. From 1959 onwards newly built Centurions incorporated the L7 at production.

Other users

The gun was subsequently adopted for use on the German Leopard 1. In addition, several countries have used the gun to improve the firepower of existing main battle tanks. Derivatives have even been mounted in Warsaw Pact-built T-54 and T-55 tanks in Israel, India, Egypt and Iraq, and Type 79 tanks in China.

Specification (L7A1)

  • Calibre: 105 mm
  • Length:
  • Barrel length: 52 calibres,
  • Recoil length:
  • Weight:
  • Rate of fire: 10 rounds per minute, 6 rounds per minute
  • Barrel life: 200 EFC
  • Maximum effective range: ,
  • Cartridge: 105×617mmR

Variants

UK models

L7A1L7A2L7A3L7A4L7 LRFJSW 105mm L7A1 L/51 Royal Ordnance 105mm IWS
  • '''FM K.4 Modelo 1L'''

Chinese models

  • Type 79/81/81A/83ZPL-79ZPL-81/AZPL-83/AZPL-94ZPL-98
  • ZPL-98A
  • '''ZPL-151'''

Other developments

  • GT-3
  • GT-7
  • Rheinmetall Rh-105 family
  • '''L74'''

Usage

L7 variant

ZPL variant

Related designs with compatible ammunition