3.7 inch Mountain Howitzer

Ordnance QF 3.7 inch mountain howitzer
A 3.7-inch QF mountain gun. Dated from 1939
Type	Mountain gun
Place of origin	United Kingdom
Service history
In service	1917–Present
Used by	Nepal (The Nepalese Army still has 90-100 in Service)
Wars	World War I, World War II
Production history
Produced	1915–?
Specifications
Weight	1,610 lb (730 kg)
Barrel length	3 ft 7.5 in (1.10 m)
Shell	20 lb HE, Shrapnel, Smoke, Starshell, HEAT
Calibre	3.7 inches (94 mm)
Recoil	Hydro-pneumatic, variable, 17.5–35 inch
Carriage	Wheeled, split trail
Elevation	−5° to +40°
Traverse	20° L & R
Muzzle velocity	973 ft/s (297 m/s)
Maximum firing range	5,899 yd (5,394 m)

Ordnance, QF 3.7-inch howitzer is a mountain gun, used by British and Commonwealth armies in World War I and World War II, and between the wars.

The British Indian Army first requested a modern mountain gun in 1906 to replace the BL 10 pounder Mountain Gun, which had been hastily developed after the Second Boer War, but itself had several shortcomings. In particular, the shell weight was seen as too light and the gun lacked any recoil absorber or recuperator, meaning the gun had to be relaid after every shell was fired. However, financial constraints delayed production of the 3.7-inch weapon until 1915. As a stop-gap, the barrel of the 10 pounder gun was mounted on an updated carriage to produce the 2.75 inch Mountain Gun.

The 3.7-inch howitzer was first introduced in 1917, and was used in action in that year in the Mesopotamian Campaign (modern Iraq area).

The 22nd (Derajat) Indian Frontier Force mountain battery arrived in the East Africa campaign on 18 December 1916, when they relieved the 28th Battery which returned to India. They appear to have re-equipped from the 10-pounder mountain gun to the 3.7-inch howitzer while in East Africa, and first used the new weapon in action in an attack on German positions at Medo, 11 April 1918.

The 3.7-inch Howitzer superseded the 2.75-inch Mountain Gun following World War I. It was used by mountain artillery regiments of the Royal Artillery and the Indian Artillery, and saw much service on the North West Frontier of India between the wars.