Military Wiki
West Spring Gun
Type Catapult
Place of origin  United Kingdom
Service history
In service 1915–1916
Used by  United Kingdom
Wars World War I
Production history
Designer Captain Allen West
Designed 1915
Manufacturer Reason Manufacturing Company
Produced 1915-1916
Weight 284 lb (129 kg)
Length 71.5 in (182 cm)
Width 18.5 in (47 cm)
Height 88 in (220 cm)
Crew 5

Effective range 240 yd (220 m)

The West Spring Gun was a bomb-throwing catapult used by British, Canadian and Australian forces during World War I. It was designed to throw a hand grenade in a high trajectory into enemy trenches. It consisted of a metal frame supporting a throwing arm powered by 24 metal springs.[1] It was invented by Captain Allen West in 1915 and manufactured by the Reason Manufacturing Company of Brighton, which was granted a patent for the device on 19 October of that year.[1][2] Although called a catapult, it was a hybrid of a ballista and a trebuchet. It required a crew of five - three to compress the springs, one to load the bomb, and one to fire as soon as the fuse was lit or the grenade pin was pulled.[3]

In tests, it could throw Mills bomb about 240 yd (220 m) or a 7 lb (3.2 kg) projectile about 80 yd (73 m) with a flight time of 6 or 7 seconds.[4] In the field it generally threw a Jam Tin Grenade, No. 15 Ball grenade, No. 21 "Spherical" grenade or No. 28 chemical grenade, equipped with a slightly longer fuse (typically 9 seconds) to ensure to reached the enemy trench before exploding.[2] It was used in combat by, amongst others, the 50th (Northumbrian) Division and the 1st Canadian Division in the Second Battle of Ypres and by Australian forces in the Gallipoli Campaign.[2][5] It was generally considered to be large and cumbersome and "generally more unwieldy" than the Leach Trench Catapult.[4] Many operators, including Captain West himself, lost fingers in the mechanism.[1] The throw could also be unpredictable, with the bomb sometimes landing near the thrower.[6]

Production of this and other trench catapults was officially halted in 1916, being replaced by the 2 inch Medium Trench Mortar and Stokes mortar.[7]


  1. 1.0 1.1 1.2 Gary Sheffield (2007). War on the Western Front: In the Trenches of World War I. Osprey Publishing. p. 201. ISBN 1846032105. 
  2. 2.0 2.1 2.2 Anthony Saunders (1999). Weapons of the Trench War: 1914-1918. Sutton. p. 65. ISBN 0750918187. 
  3. Clifford Almon Wells (1917). From Montreal to Vimy Ridge and beyond: the correspondence of Lieut. Clifford Almon Wells, B.A., of the 8th battalion, Canadians, B.e.f., November, 1915-April, 1917. George H. Doran company. p. 87. 
  4. 4.0 4.1 "Error: no |title= specified when using {{Cite web}}". The Institution of Royal Engineers. 1925. p. 79. 
  5. Kenneth Radley (2006). We lead, others follow: First Canadian Division, 1914-1918. Vanwell. p. 120. ISBN 1551251000. 
  6. "Grenade, West Spring Gun, No 21 R Type". Imperial War Museum. 
  7. Hugh Chisholm (1922). The Encyclopædia Britannica: The New Volumes, Constituting, in Combination with the Twenty-nine Volumes of the Eleventh Edition, the Twelfth Edition of that Work, and Also Supplying a New, Distinctive, and Independent Library of Reference Dealing with Events and Developments of the Period 1910 to 1921 Inclusive, Volume 1. Encyclopædia Britannica Company Limited. p. 470. 

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