BL 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.
|Place of origin||United Kingdom of Great Britain and Ireland|
|Used by||United Kingdom of Great Britain and Ireland
|Wars||World War I|
|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
(HE) 5,800 yds (5,303 m) 
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.
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It was superseded at the end of World War I by the QF 3.7-inch mountain howitzer.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
Notes and references
- Hogg & Thurston 1972, page 42
- "Camel artillery ready to fire". New Zealand History. Ministry for Culture and Heritage. 15 July 2013. Retrieved 2 January 2014.
- Dale Clarke, British Artillery 1914-1919. Field Army Artillery. Osprey Publishing, Oxford UK, 2004 ISBN 1-84176-688-7
- Hogg, Ian; 2000; Twentieth Century Artillery; Amber Books, Ltd., ISBN 1-58663-299-X
- I.V. Hogg & L.F. Thurston, British Artillery Weapons & Ammunition. London: Ian Allan, 1972
|Wikimedia Commons has media related to BL 2.75 inch Mountain Gun.|
- Handbook of the 2.75-inch B.L. gun : Mule equipment. London : H.M.S.O. 1920 at State Library of Victoria
- Gun drill for 2.75 inch B.L. gun converted MK I and MK I carriage mark I 1921,1923 at State Library of Victoria
- 2.75 inch Mountain Gun at Landships