Royal Ordnance L7

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The Royal Ordnance L7 is the basic model of Britain's most successful tank gun. The L7 was a 105 mm rifled design intended for use in armored fighting vehicles. It was so successful that it armed not only British post-war designs, but was used almost universally in "the West" as the main armament of almost every main battle tank.

The L7 was developed by Britain's Royal Ordnance Factories to equip of the postwar (Cold War) period as the successor to the 20 pounder used on Britain's postwar tank - the Centurion.

The L7 was a popular weapon and it was maintained in use even after it was superseded by the L11 series 120 mm rifled tank gun for some Centurion tanks operating as Artillery Forward Observation and AVRE vehicles. The L7, and adaptations of it, can be found today as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War. It is also being used as the main armament of the US Army's newest direct-fire weapon, the Stryker.

Contents

1 History
2 Specification

2.1 Ammunition Available

3 Variants
4 Use
5 See also

History

As a direct replacement for the 20 pdr, which was seen as incapable of defeating the current and future Warsaw Pact tank designs (T-55 and IS-3), the L7 was specifically designed to fit into the turret mountings of the 20-pounder. This would enable the Centurions to be upgunned with a minimum of modifications and hence the fleet could be upgraded in a shorter time and at a lower cost.

The breech uses a horizontally-sliding breech block for loading the fixed cartridge cases. The gun recoils approximately 29 cm (in most applications), automatically ejects the empty cartridge case upon reaching full recoil. The barrel of the L7 is fitted with a bore evacuator approximately halfway down its length. It is eccentrically mounted, which is a key recognition feature.

The first tank to be equipped with the L7 was the Centurion Mark 5 in 1959. The gun was subsequently adopted by several other nations for their own MBTs, most notably the German Leopard 1 (for which the L7A3 variant was developed), the Japanese Type 74 (produced under license by Japan Steel Works), the Swedish Stridsvagn 103 (as the L74, with a longer barrel and automatic loader), the US M60 series of tanks (with the M68), and the Israeli Merkava. In addition, several countries have used the gun to improve the firepower of existing MBTs.

Specification

Caliber: 105 mm
Weight: 1,282 kg
Length: 5.89 m
Rate of fire: 10 rounds per minute (maximum)

Ammunition Available

APDS
APERS-T ("Anti-personnel-tracer")
APFSDS
Dummy
HE
HEAT
HESH
Smoke-White phosphorus incendiary
Target Practice
Target Practice Discarding Sabot

Variants

L7A1

Standard British production variant.

L7A3

Variant for the (West) German Leopard 1 MBT. The upper rear corner of the breech block reduced in size so gun can be depressed without hitting the turret roof.

L74

Swedish variant with a 62 calibre (6.51 m) barrel used only for the Stridsvagn 103 MBT.

M68

US built variant for M60 Patton. Utilises a round breech with a vertically-sliding breech block, and a different design of bore evacuator.

Type 79/81/83

Chinese copies of an L7 supplied by Austria.