Ordnance QF 3.7in mountain or pack howitzer

The Ordnance QF 3.7in Howitzer (known as a pack or mountain howitzer) was designed to be carried by mules, and was the last in a series of ‘screw guns’ used by the British and Indian Armies.

The best way to move heavy loads around the mountains on the borders of the British Empire was by mule, but individual mules would only carry a load of 200lb. In 1879 Col Le Mesurier of the Royal Artillery came up with a design for a gun with a barrel that could be split into two, and screwed together. This entered service as the Ordnance, Jointed, Rifled Muzzle Loading 2.5in. This was the first of a series of similar designs, ending with this 3.7in howitzer.

Work on the design began at Vickers in 1910 in response to a request from the Indian government for a howitzer to be used alongside the 2.75in mountain gun. However a shortage of funds meant that it didn’t go into production until 1915.

The 3.7in howitzer was the first artillery piece with a split-trail carriage to enter British service. This gave it a better range of traverse than most of its contemporaries, very useful in the rugged terrain of the north-west frontier. It had rugged recoil spades at the ends of each trail, designed to be bashed into the ground using sledgehammers. It had a large shield, and a hydro-pneumatic recoil system with variable amounts of recoil at different elevations. The howitzer could be split into eight loads - two for the two halves of the barrel, and six for the carriage.

The carriage Mk.II was designed to be towed by draught animals. The carriage Mk.III had fixed spades instead of the removable spades of the Mk.I.

Between the wars it was given pneumatic-tyres wheels to make it possible to tow it by motor vehicles (as the Carriage Mk.IV, towed behind ‘Light Dragon’ tracked vehicles). In this format it was also give an ammunition trailer.

In the inter-war years the 3.7in howitzer saw a wide range of uses. It was used with the Light Batteries of the Experimental Armoured Force, replaced the 13-pounder with the Royal Horse Artillery and the 12-pounder 8cwt as the Royal Navy’s Landing Gun.

The 3.7in howitzer remained in service throughout the Second World War. It was used by the new airborne units, before being replaced by the American 75mm Pack Howitzer, a slightly lighter weapon. The Royal Marines used it as a landing gun. Its main use was in Burma, where it was well suited to the difficult terrain. It was also used in East Africa, North Africa and Italy.

In 1944 the specification was issued for a 3.3in howitzer that was intended to replace this weapon, but despite many years of effort this weapon never appeared, and work on it ended in the mid 1950s. The 3.7in howitzer slightly outlived that project, and was declared obsolete in February 1960.


Ordnance QF 3.7in mountain howitzer Mk.I on carriage QF mountain howitzer Mk I to IV



Barrel Length


Weight for transport


Weight in action





40 degrees

Shell Weight

20lb (9kg) HE
20lb (9kg) Shrapnel

Muzzle Velocity


Maximum Range

4,500 yards (4,130m) HE
6,000 yards (5,500m) Shrapnel

Rate of Fire


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How to cite this article: Rickard, J (14 November 2018), Ordnance QF 3.7in mountain or pack howitzer , http://www.historyofwar.org/articles/weapons_ordnance_QF_3_7in_mountain_howitzer.html

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