BL 12-inch railway howitzer

The Ordnance BL 12 inch howitzer on truck, railway was developed following the success of the 9.2 inch siege howitzer. It was similar but unrelated to the 12 inch siege howitzers Mk II and IV.

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 in World War I, usually in 2-gun batteries, operated by the Royal Garrison Artillery.

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

