The 2.75 inch mountain gun, developed in 1911 and introduced in 1914, was a replacement for the 10 pounder mountain gun. Both were designed as ‘screw guns’, guns able to be dismantled into small parts, and especially for the heaviest part, the barrel, to be split in two, for transportation in six parts in total by mule, horse or other pack animal – even camel! It was not to be until halfway through the war that mountain units were widely replaced with the 2.75 inch mountain gun, the mountain artillery units that served all Gallipoli all appear to have been equipped with the 10 pounder until they left the campaign at the end of 1915/January 1916 and were refitted, usually in Egypt. The light weight of the guns and their ease of transportation meant they were very popular weapons in the Middle East theatre, such as Palestine and Mesopotamia, and also on the Macedonian front (known as Salonika), where the 4th (Highland) Mountain Brigade, Royal Garrison Artillery used them, as the guns were so well suited to the mountainous terrain found in that theatre. The ‘normal’ territory for mountain guns was of course the infamous North West frontier, where they also served both during and after the Great War.

The 2.75 inch mountain gun is stated to have the same barrel as the 10 pounder – inspection of surviving examples seems to confirm this, as there seems to be only detailed differences between the two, such as a more pronounced flare on the muzzle of the 2.75 inch gun. The 2.75 inch gun was the first mountain artillery to have a recoil system, and as well as the recoil system apparatus it also featured a new carriage and a wide gunshield which could be folded. The shell weight was also increased, from 10lbs to 12.5lbs. 183 were built in total, weighing 1,292lbs (586kg) it had a rate of fire of seven to eight rounds a minute using a separate loading shell (meaning unlike quick firing 18 pounder guns where the shell is complete with the brass cordite casing and primer, the cordite is a separate charge and so the shell has to be loaded and then the charge, and then a friction tube to ignite the charge) and a range of 5,600 yards, firing high shrapnel shells or 5,800 yards for high explosive. At least one photograph exists of a 2.75 inch mountain gun of the 4 th Highland Mountain Brigade RGA in Salonika being used as an anti-aircraft gun with the shield removed and the front part of the carriage (where the wheels are) placed high with the rear of the carriage on the ground, providing a high elevation to augment the weapon’s elevation of -15 degrees to +22 degrees, and with a limited traverse of four degrees each side. The recoil length was very impressive compared to the small size of the gun – some Great War photographs and footage of these weapons show one of the gunners almost knocked over by the long and sharp recoil which could make the entire gun jump, which in one photograph is sometimes incorrectly captioned as showing the gunner being shot.

Although replaced by the 3.7 inch mountain gun at the end of the Great War, photos show the 2.75 inch mountain gun still in use in the 1930’s.

Today, a surviving example is at the Heugh Battery Museum in Hartlepool, North-east England, and is the subject of the following images.

There are film clips of the 2.75" Mountain Gun on the IWM website.

British artillery on the Salonika front has 2.75" Mountain Guns firing in the first 3:16 mins of the clip.
Assembly of a mountain gun shows a 2.75" Mountain Gun being assembled in the first 1:08 mins of the clip.

No kits are known to exist in 1/76 or 1/72, but a 28mm Wargame model is produced by Brigade Models.