The Ordnance BL 12 inch howitzer on truck, railway was developed following the success of the 9.2 inch siege howitzer

BL 9.2 inch Howitzer

The Ordnance BL 9.2 inch howitzer was the principal counter-battery equipment of British forces in France in World War I. It equipped a substantial number of siege batteries of the Royal Garrison Artillery...

. It was similar but unrelated to the 12 inch siege howitzers Mk II and IV

BL 12 inch Howitzer

The Ordnance BL 12 inch howitzer was a scaled-up version of the successful 9.2 inch siege howitzer.-History:Following the success of their BL 9.2 inch Howitzer, Vickers designed an almost identical version scaled up to a calibre of 12 inch, the Mk II entering service on the Western...

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Mark I

Mk I was introduced from March 1916. It is identified by its short barrel and recuperator above the barrel.

Mark III

The longer-barrelled Mk III soon followed, with a heavier breech to balance the gun. It retained the recuperator above the barrel.

Mark V

Mk V, dating from July 1917, moved the recoil buffer and recuperator into a single housing below the barrel, which was common for all new British artillery developed during World War I. It also had a lighter breech with the gun balanced by the redesigned recoil system and altered gun positioning on the cradle. Mk V also relocated the loading platform from the railway wagon to the revolving gun mounting, which now allowed 120° of traverse, and by overhanging the opposite side provided crew access when the gun fired to the side (90° traverse) and also helped to balance it.

Combat service

All 3 versions served on the Western Front

Western Front (World War I)

Following the outbreak of World War I in 1914, the German Army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne...

 in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, usually in 2-gun batteries, operated by the Royal Garrison Artillery

Royal Garrison Artillery

The Royal Garrison Artillery was an arm of the Royal Artillery that was originally tasked with manning the guns of the British Empire's forts and fortresses, including coastal artillery batteries, the heavy gun batteries attached to each infantry division, and the guns of the siege...

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Mk III and MK V were deployed for the home defence of Great Britain in World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

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Further reading

• Harry W Miller, United States Army Ordnance Department, Railway Artillery: A Report on the Characteristics, Scope of Utility, Etc., of Railway Artillery, Volume II, Pages 136-145. Washington : Government Print Office, 1921

External links