BL 12-inch howitzer

The Ordnance BL 12-inch howitzer was a scaled-up version of the successful BL 9.2-inch siege howitzer.

BL 12-inch howitzer
Class Vehicle
Type Towed Artillery
Manufacturer Vickers Limited
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1916
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) 1916 1945 View
ManufacturerName Production From Production To Quantity
Vickers Limited View

Following the success of their BL 9.2-inch howitzer, Vickers designed an almost identical version scaled up to a calibre of 12 inches, the Mk II entering service on the Western Front in August 1916. Eight complete equipments are reported as arriving in August 1916 and being in action in France shortly afterwards.

It was similar but unrelated to the BL 12 inch railway howitzers Mk I, III and V produced by the Elswick Ordnance Company at the same time.

The Mk IV was a more powerful version with longer barrel produced from 1917.

Later models were used for British home defence in World War II.

As with other large-calibre weapons, it was operated by the Royal Garrison Artillery in World War I.

The 12-inch was dismantled and transported in six loads mounted on traction engine wheels. It was then reassembled on its static siege mounting on top of a steel "holdfast", with 22 tons of earth in a box sitting on the front of the holdfast in front of the gun, to counteract the kick of firing.

Type Heavy siege howitzer
Place of origin United Kingdom
Service history
In service 1916 - 1945
Used by UK and Commonwealth
Wars World War I, World War II
Production history
Designer Vickers
Manufacturer Vickers
Number built 14 (Mk II); 43 (Mk IV)
Variants Mk II, Mk IV
Barrel length 160 inch (Mk II)
207.6 inch (Mk IV)
Shell HE 750 lb (340 kg)
Calibre 12 inches (304.8 mm)
Recoil Variable hydropneumatic
Carriage siege carriage
Maximum firing range 11,340 yd (10.37 km) (Mk II)
14,350 yd (13.12 km) (Mk IV)

End notes