Ordnance QF 25-pounder

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Ordnance QF 25 pounder
British 25 pounder Quick firing Mark II gun at the Imperial War Museum.jpg
A QF 25 pounder Mark II (without muzzle brake) mounted on a Mk I Carriage at the Imperial War Museum, London.
TypeField gun / howitzer
Place of origin United Kingdom
Service history
In service1930's to 1967. Still in use in Irish Reserve Defence Force (RDF)
Used byCommonwealth, Free Forces and others
WarsWorld War II, Korea and others
Production history
Designed1930's
VariantsMarks I, II, III and Short
Specifications
Mass1.8 tonnes
Length18 ft 2 in (5.53 m) from muzzle brake to tip of handspike
Barrel length31 calibres
Width7 feet wheelbase (Mk 1 carriage)
Crew6

ShellNormal, Super
Calibre3.45 in (87.6 mm)
BreechVertical sliding block
RecoilHydropneumatic
CarriageBox trail
Elevation-5 to 45 degrees (70 degrees with modified sight mount and digging)
Traverse360° on platform, 4° left and right on carriage
Rate of fire6-8 round/min at Gunfire
Muzzle velocity1700 ft/s Charge Super
Maximum firing range13,400 yd Charge Super
Feed systemSingle shot, breech loaded
SightsIndirect fire - calibrating and reciprocating; direct fire - telescope

The Ordnance QF 25 pounder, or more simply, 25-pounder or 25-pdr, was the major British field gun/howitzer that was introduced into service just before World War II to replace the 18 pounder Gun and 4.5 inch Howitzer. It was the British Army's primary artillery field piece into the 1960s. It was considered by many to be the best field artillery piece of the war, combining high rates of fire with a reasonably lethal shell in a highly mobile piece. Smaller numbers served in training in the United Kingdom until the 1980s, while many Commonwealth of Nations countries used theirs until about the 1970s. Since leaving UK service the 25 pounder has been used in combat during the Battle of Mirbat in 1972 in Oman. One of the last uses of the 25-pounder in combat was by the Cypriot National Guard during the 1974 Turkish invasion of Cyprus and by Kurds in N Iraq 2003. Ammunition for the weapon is currently produced by Pakistan Ordnance Factories.

Design

The design was the result of extended studies looking to replace both the 18 pounder (84 mm) field gun and the 4.5 inch (114 mm) howitzer, which had been the main field artillery equipments during the First World War. The basic idea was to build a single weapon with the direct-fire capability of the 18 pounder and the high-angle fire of the howitzer, firing a shell about half way between the two in size, around 3.5 to 4 in (90 to 100 mm) of about 30 pounds (14 kg).

Development during the inter-war period was severely hampered by a lack of money, and it was eventually decided to build a "new" design from existing 18 pounders by converting barrels, but designing a new barrel and carriage for production when funds were available. The result was a 3.45 in (87.6 mm) weapon firing a 25 pound (11 kg) HE shell. It was mounted on late model 18 pounder carriages. One of these used a firing platform and this configuration was adopted for the new build guns. The firing platform was lowered and the gun pulled onto it, providing a flat surface that allowed the gunners to quickly turn the weapon in any direction.

A 25-pdr field gun and limber being towed by a Morris-Commercial Quad, crossing a pontoon bridge at Slaght Bridge in Antrim, Northern Ireland, 26 June 1942.

Unlike the 18 pounder, the 25 pounder used howitzer type variable charge ammunition. For the Mk 1 Ordnance on 18 pounder carriage this was limited to three different "charges", Charge 1, 2 and 3 in a single cartridge. The 'proper' 25-pdr, Mk 2 Ordnance on Mk 1 Carriage, also had charge super in a separate cartridge. An increment for charge super was introduced in 1942 to provide higher velocity for anti-tank shot. Subsequently these increments were added to charges 2 and 3 to give an additional three combinations charges for use with upper register (high angle) fire. The introduction of the increment to charge super necessitated the addition of the muzzle-brake. 25-pdr was separate loading, the shell was loaded and rammed then the cartridge in its brass case was loaded and the breech closed. In British terminology the 25 pounder was called "QF" because the cartridge case provided obturation (it provided the gas seal in the breech).

In common with all British guns of the period the indirect fire sight was 'calibrating'. This meant that the range, not elevation angle, was set on the sight. The sight compensated for the difference in the gun's muzzle velocities from standard. The gun was also fitted with a direct fire telescope for use with armour piercing shot. It also used 'one man laying' in accordance with normal British practice.

An important part of the gun was the ammunition limber (trailer). The gun was hitched to it and the trailer hitched to the tractor when on tow. However, the gun did not need a limber and could be hooked directly to a tractor. The trailer carried ammunition (thirty-two rounds). Ammunition was also carried in the gun tractor along with the detachment and various gun stores. Some stores, such as sights, were carried cased on the gun. Each section (two guns) had a third tractor that carried ammunition and towed two ammunition trailers.

The gun detachment comprised the following: No 1 - detachment commander (a sergeant), No 2 - operated the breech and rammed the shell, No 3 - layer, No 4 - loader, No 5 - ammunition, No 6 - ammunition, normally the 'coverer' - second in command and responsible for ammunition preparation and operating the fuze indicator.

The official 'reduced detachment' was 4 men.

25 pounder projectile CMHM Brantford.JPG

Ammunition

The 25 pounder's main ammunition was the High Explosive (HE) shell, but it could fire base ejection smoke, star and flare shells, chemical shells, and smoke shells were sometimes reloaded with propaganda leaflets. In the direct fire role, the 25 pdr was also supplied with a limited amount of 20 pound (9 kg) solid armour piercing (AP) shot, later replaced with a more potent version with a ballistic cap. A shaped charge anti-tank shell was under development in Canada, but the introduction of the 17 Pounder dedicated anti-tank gun ended its development. After the Second World War UK replaced AP shot with a HESH shell.

Service

An Australian 25 Pounder at El Alamein in July 1942 (AWM 024515).

The 25 pounder was the main field artillery gun used by British Commonwealth infantry and armoured divisions of all types during the Second World War. Throughout the war each British-pattern infantry division was established with seventy two 25 pounders. After mid 1940 each of the division's three field Regiments being issued with 24 guns organised into three 8 gun batteries, before mid 1940 each regiment had two batteries of 12 guns. Armoured divisions had two regiments, from 1944 one of these was equipped with the self-propelled 25-pdr nicknamed Sexton.

Normally gun was towed, with its limber, usually behind a Morris C8 4x4 Field Artillery Tractor called a "Quad". The early 18/25 pdrs had been towed in the field by the Dragon Medium Mark IV a tracked vehicle derived from a light tank. After seeing the utility of the M7 Priest, the British introduced the similar Canadian-designed and -built Sexton, mounting the 25 pdr on a Ram tank chassis (itself based on the M3 Lee). Before Sexton the Bishop had been introduced using the Valentine tank chassis.

Even by WWII standards, the 25 pdr was at the smaller-end of the scale although it had longer range than most other field equipments. However, it was designed to support the proven British doctrine of suppressive (neutralising) fire, not the concept of destructive fire that had proved illusory in the early years of World War I. Most forces had entered the war with even smaller 75 mm designs, but had quickly moved to 105 mm and larger weapons. Nevertheless the 25 pdr was considered by all to be one of the best artillery pieces in use. The devastation caused by the gun (and the speed at which the British artillery control system could respond) in Normandy and the rest of North-West Europe made many German soldiers believe that the British had secretly deployed an automatic 25 pounder. The introduction of NATO standardization led to the replacement of the gun with the 105 mm.


The gun known as the G1 was extensively used in the early stages of the South African Border War by the South African Defence Force, including Operation Savannah. The G1 is still used in the ceremonial role. The Rhodesian Army used the weapon during the Bush War, but by this stage the round couldn't penetrate enemy bunkers. The last British military unit to fire the gun in its field role (as opposed to in a ceremonial role) was the Gun Troop of the Honourable Artillery Company on Salisbury Plain in 1992.

The gun was extensively used by the Sri Lankan Army during the early years of the Sri Lankan civil war. It still remains in service although only in a ceremonial role.

The MkIII is still in service in the Irish Reserve Defence Forces (RDF) and a significant number are held in active reserve by the Cypriot National Guard. The Irish Army also maintain a 6 gun ceremonial 25pdr battery for use in state occasions. The 25pdr is the longest serving weapon in the Irish Army, having been introduced in 1949, and continuing to be popular with gun crews today.

Variants

Mark I

Known officially as the Ordnance, Quick Firing 25 pounder Mark I on Carriage 18-pr Mark IV, or Ordnance, Quick Firing 25 pounder Mark I on Carriage 18-pr Mark V and commonly called the 18/25-pr. The Mark IV carriage was a box trail, Mark V was a split trail. These conversions of the 18 pdr first entered British service in the late 1930s. A few were lost in the Norwegian campaign and 704 in France, leaving about the same number in UK's global stocks. They served in North Africa (until about late 1941) and Malaya. This mark of 25 pdr was limited to charge 3 due to its 18 pdr carriage.

Those captured by the Germans, who liked them so much they built up entire artillery units based on them. These units were deployed in Normandy prior to D-Day, leading to somewhat ironic duels between 25 pdr units on either side. In some cases the Germans won the duel.

Mark II

25-pounder with a muzzle brake.

The Mark II, fitted to the Mark 1 carriage was the standard gun during World War 2. They were built in Australia and Canada but mostly in UK. Deliveries (from UK production) started at the beginning of 1940 and first entered service with a Canadian regiment stationed in UK during May 1940. No Ordnance 25-pr Mk 2 on Carriage 25-pr Mark 1 were lost in France. This gun fired all charges, 1 - 3 and Super. A later addition were charge increments. These were added to Charge Super for direct fire anti-tank and necessitated the adoption of a muzzle brake to reduce recoil. Guns with this modification were known as the Mark 2/1. The distinctive brake is a well-known feature of the gun that makes it easily recognized.

Mark III

The Mark III ordnance was a Mk. II with a modified receiver to prevent the rounds from slipping back out when loading at high angles. With the muzzle brake they became the Mark III/1, while the Mark IV were identical new-build versions which all featured the brake.

In Burma a local modification produced a narrower wheelbase (by about 20-inches) called the Jury Axle. This was suitable for towing by Jeep and could be loaded into a Dakota aircraft. It was subsequently adopted officially with other minor modifications and a new platform for the narrow wheelbase as the Carriage 25 pdr Mark 2. The Mark 3 Carriage, also narrow, included a hinge to make it easier to fire the gun in the upper register (high angle). High angle fire had been introduced in Italy and used the increments originally introduced for anti-tank fire, adding them to charges 2 and 3 to give 25-pdr 7 charges.

Short, Mark I

A Short 25 Pounder in New Guinea in 1944 (AWM 075609).

The 25 pounder Short Mark I, or Baby 25 pr, was an Australian pack gun version of the 25 pounder, first produced in 1943. This was a shortened version of the standard 25 pounder, mounted on the Carriage 25 pr Light, Mark 1. The Baby was intended for jungle combat and was used by only Australian units in the South West Pacific Theatre, during World War II. The gun could be towed by a light vehicle or broken down into 13 sections. During the campaign in New Guinea the gun could be manhandled up steep jungle tracks where trucks could not operate.

Notes

References

Various QF 25-pr Range Tables Part 1 1939 - 1967 Various QF 25-pr UK Gun Drill pamphlets 1939 - 1976 Various QF 25-pr Handbooks 1940 - 1957

External links