12 inch Howitzer

12 inch Howitzer

The 12 inch Howitzer was first introduced in 1917. It was mostly an enlarged version of the 9.2 inch Mark 2 using a similar siege mounting. It was moved in six loads drawn by traction engines or Holt caterpillar tractors. It was no wonder the troops called it the “12 inch Road Hog”. It was provided with a power rammer which was probably the first ever used on a field equipment.
Those guns still remaining in WW2 were deployed in 1940 in anti-invasion positions. In 1943 a “Siege Train” was proposed and an anti-concrete shell designed. The idea was dropped and the shells never produced. The 12 inch Howitzer was declared obsolete in March 1945.


Weight of Gun & Breech Mechanism20,440 lbs
Total Length222.35 inches
Length of Bore207.6 inches (17.3 calibres)
Rifling60 grooves, uniform right hand 1/20
Breech MechanismAsbury interrupted screw, percussion fired
Elevation+20° to +65° (loading angle +3½º hand, +19½º hydraulic)
Traverse30° right & left
Recoil SystemHydropneumatic constant, 50 inches
Weight in Action37½ tons plus 20 tons of earth in front box


Firing standard 750 lb HE Shell

Muzzle velocity1,468 feet per second
Maximum range14,350 yards


Shell, HE Mark 10Nose fuzed, non-streamlined. Percussion Fuze
No. 106 or No. 106E
Shell, Common Pointed Mark 1ANon-streamlined, pointed with base Percussion Fuze No. 16. For hard targets
Shell, Concrete Piercing Mark 1The requirement lapsed and it never entered production
Propelling Charge2 distinct assemblies. Short Range Portion – charges 1 to 6. Long Range Portion – charges 7 to 11.
The Royal Artillery 1939-45