Ordnance QF 20 pounder

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Ordnance QF 20 pounder Mark I
Charioteer-latrun-2.jpg
Charioteer tank equipped with the 20 pounder. This gun is a later model which is fitted with a bore evacuator
Type tank gun
Place of origin  United Kingdom
Service history
In service 1948-1970s
Used by  United Kingdom
 Australia
 Austria
 Canada
 Finland
 Israel
 Jordan
 Lebanon
 South Africa
Wars Korean War
Vietnam War
Six Day War
South African Border War
Specifications
Length 226.4 in (5.75 m)

Shell 20 pounds (9.07 kg)
Calibre 84 millimetres (3.31 in)
Elevation +18 to -10 in Centurion Mk 5

The Ordnance QF 20 pounder (simply known as 20 pounder or 20-pr) was a British 84 mm (3.307 inch)[1] tank gun

It was introduced in 1948 and used in the Centurion main battle tank, Charioteer medium tank, and Caernarvon Mark II heavy tank.

It was the improved successor to the effective Ordnance QF 17 pounder and the predecessor of the 105 mm L7 gun.

Design and Development[edit]

The gun was developed by the Royal Ordnance Factories.

As fitted to the Charioteer, it ran through two models:

  • Model A without a fume extractor.
  • Model B with a fume extractor.

The L7 105 mm tank gun was developed from the 20 pounder. In 1954, the original version of the 105 mm was made by re-boring the tube of a 20 pounder barrel.[2]

Service history[edit]

The gun was fitted predominantly to the Centurion tank, seeing action with British and Australian forces.

One gun was fitted to a Swiss pre-production Panzer 58.[3]

Performance[edit]

The 20 pounder's APCBC projectile had an initial muzzle velocity of 1,020 metres per second and could penetrate 210mm of rolled homogeneous armour (RHA). However, these conventional rounds were rarely used.

The APDS projectile had a muzzle velocity of 1,465 m/s (4,810 ft/s) and could penetrate 30 cm (12 in) of RHA.[4][5]

The 20-pounder could also fire high-explosive and canister shot shells.

Ammunition[edit]

20 pdr HE round
Round Muzzle velocity[6]
APDS 4,700 ft/s
HE 1,975 ft/s
Canister 3,000 ft/s
Smoke 825 ft/s

Notes[edit]

  1. ^ Pugh, p.34; the gun is specified as 83.4 mm (3.283 in) here, while Ogorkiewiecz states the weapon was 83.8 mm. Norman gives it as "3.3 inch (84 mm)"
  2. ^ Ogorkiewicz, p. 70.
  3. ^ *Ford, Roger (1997). The World's Great Tanks from 1916 to the present day. Brown Packaging Books Ltd. p. 121. ISBN 1-897884-29-X. 
  4. ^ British Anti-Tank Gunnery Data at www.figuras.miniatures.de
  5. ^ Dunstan, p. 10, notes the 20 pounder's APDS round had twice the penetration capability of an 8.8 cm AP round.
  6. ^ Norman p12

References[edit]

  • Dunstan, Simon. Centurion Universal Tank 1943-2003, Oxford: Osprey Publishing, 2003. ISBN 1-84176-387-X.
  • Ogorkiewicz, Richard. Technology of Tanks, London: Jane's Information Group, Ltd., 1991. ISBN 0-7106-0595-1.
  • Pugh, Stevenson (1962). Fighting Vehicles and Weapons of the Modern British Army. Macdonald & Co. OCLC 10010960. 
  • Norman, Michael. Armour in Profile No. 23 Centurion 5. Surrey: Profile Publications. 

See also[edit]

External links[edit]