2.75 inch Mountain Gun

Ordnance BL 2.75 inch mountain gun
Men of the 4th (Highland) Mountain Brigade with 2.75-inch (70 mm) mountain gun, Kamberli, Salonika front, June 1918.
Type	Mountain artillery
Place of origin	United Kingdom of Great Britain and Ireland
Service history
In service	1914–1919
Used by	United Kingdom of Great Britain and Ireland British Raj
Wars	World War I
Production history
No. built	183
Specifications
Weight	586 kg (1,292 lb)
Barrel length	72.5 inch (1.84 m)
Shell	Separate loading Breech Loading 5.67 kg (12.5 lb)
Caliber	2.75-inch (70 mm)
Recoil	Hydro-spring, constant, 38 inches (970 mm)
Carriage	Wheeled,single pole trail
Elevation	-15° - 22°
Traverse	4° L & R
Muzzle velocity	1,290 ft/s (393 m/s)
Maximum firing range	(shrapnel) 5,600 yds (5,120 m) (HE) 5,800 yds (5,303 m)

The Ordnance BL 2.75-inch mountain gun was a screw gun designed for and used by the Indian Mountain Artillery into World War I.

The gun was an improved version of the 1901 BL 10-pounder mountain gun.

The new 1911 version improved on the 1901 gun with a new pole trail, recoil buffer, recuperator and gunshield, and increased shell weight from 10 to 12.5 lb (5.7 kg). It was a screw gun design, where the barrel could be separated into two parts via a screw joint. This allowed for the gun to have a heavier barrel, but still be broken into smaller portions for transport by mule teams. This was important for a weapon designed to be used in mountainous and rough terrain, or where adequate vehicle and horse transport was not readily available. The weapon could be carried by six mules or towed.

The gun was adopted in 1911 and began entering service in 1914.

The weapon served primarily with the Indian Mountain Artillery in the northwest portion of British Indian territory (on what is now the border between Pakistan and Afghanistan) and participated in British-led military action in that theatre.

It also served in Mesopotamia and the Salonika front during World War I.

Due to its specialised nature the gun was produced in only limited numbers, with just 183 manufactured during the war.

It was superseded at the end of World War I by the QF 3.7-inch mountain howitzer.

A 2.75-inch mountain gun is on display at the Heugh Battery Museum, Hartlepool