Ordnance QF 25-pounder

Ordnance QF 25-pounder
Ordnance QF 25-pounder gun shown mounted on its firing platform, King Street West, Dundas, Hamilton, Canada.
Type	Field gun/Howitzer
Place of origin	United Kingdom
Service history
In service	1940–present
Used by	See users
Wars	World War II Malayan Emergency Korean war Rhodesian Bush War South African Border War Dhofar Rebellion Turkish invasion of Cyprus Sri Lankan Civil War Iraqi insurgency
Production history
Designed	1930s
Manufacturer	Royal Ordnance
Variants	See variants
Specifications (Mk II on Carriage Mk I)
Weight	1,633 kg (3,600 lb)
Length	4.6 m (15 ft 1 in) muzzle to towing eye
Barrel length	2.47 m (8 ft 1 in) (28 cal)
Width	2.13 m (7 ft) at wheel hubs
Height	1.16 m (3 ft 10 in) trunnion height
Crew	6

Shell	High explosive Anti-tank Smoke
Shell weight	11.5 kg (25 lb) (HE including fuze)
Calibre	87.6 mm (3.45 in)
Breech	Vertical sliding block
Recoil	Hydro-pneumatic
Elevation	-5° to 45° (80° with dial sight adapter and digging trail pit or wheel mounds)
Traverse	4° Left & Right (top traverse) 360° (platform)
Rate of fire	Gunfire, 6–8 rpm Intense, 5 rpm Rapid, 4 rpm Normal, 3 rpm Slow, 2 rpm Very slow, 1 rpm
Muzzle velocity	198 to 532 m/s (650 to 1,750 ft/s)
Maximum firing range	12,253 m (13,400 yd) (HE shell)
Sights	Calibrating & reciprocating

The Ordnance QF 25-pounder, or more simply 25-pounder or 25-pdr, was the major British field gun and howitzer during World War II. It was introduced into service just before the war started, combining high-angle and direct-fire, relatively high rates of fire, and a reasonably lethal shell in a highly mobile piece. It remained the British Army's primary artillery field piece well into the 1960s, with smaller numbers serving in training units until the 1980s. Many Commonwealth of Nations countries used theirs in active or reserve service until about the 1970s and ammunition for the weapon is currently being produced by Pakistan Ordnance Factories.

Design

The design was the result of extended studies looking to replace the 18-pounder (3.3 inches (84 mm) bore) field gun and the 4.5-inch howitzer (114.3 mm bore), which had been the main field artillery equipments during the First World War. The basic idea was to build one weapon with the high velocity of the 18-pounder and the variable propelling charges of the howitzer, firing a shell about half way between the two in size, around 3.5–4.0 inches (89–102 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 inches (87.6 mm) weapon firing a shell weighing 25 pounds (11.3 kg). It was mounted on late model 18-pounder carriages. One of these used a circular firing platform and this was adopted for the new guns. The firing platform was attached to the gun and when lowered the gun was pulled onto it. This platform transferred most of the recoil forces to the ground, instead of using the spade at the end of the trail, making the gun very stable when firing. It also provided a flat smooth surface for the carriage to rotate on using the road wheels, this enabled the gunners to traverse the carriage quickly in any direction.

A 25-pounder 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. The 25-pounder 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 "quick firing" (QF), originally because the cartridge case provided rapid loading compared with bag charges, and was automatically released when the breech was opened.

The use of separate shell and cartridge allowed the charge to be changed for different ranges. For the Mk 1 Ordnance on an 18-pounder carriage there were three "charges", charges one, two and three, all of which could be used in the common cartridge design. The Mk 2 Ordnance on Mk 1 carriage added a "super" charge in a different cartridge. In 1943 a separately bagged "increment" charge was added; used with the Super it provided higher velocity for anti-tank use. The introduction of the increment to super was only possible following the addition of the muzzle-brake in the previous year. Subsequently another type of increment was introduced to be added to charges one and two to provide additional combinations for use in high angle fire. However, this fire required a dial sight adaptor, removal of the platform and some excavation of the ground.

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 trailer ("trailer, artillery, No 27"). The gun was hooked to it and the trailer hooked to the tractor for towing. The gun did not need a limber^[1] and could be hooked directly to a tractor. The trailer provided the brakes as only a hand-brake was fitted to the gun carriage. The trailer carried ammunition; thirty-two rounds in trays (two rounds per tray) in the trailer protected by two doors. Ammunition was also carried in the gun tractor 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 four men.

Many different companies manufactured the guns and component parts in the UK. Vickers Armstrong in Scotswood, Baker Perkins in Peterborough and Weirs in Glasgow were some of the most significant. The various Royal Ordnance factories produced most of the ordnance components. In Canada, Sorel Industries built complete guns and provided the ordnance for fitting to the Sexton. Australia also built complete guns, choosing to weld the carriages rather than rivet, as was the practice in the UK and Canada. In all, over 13,000 were made worldwide.

Ammunition

"Normal" cartridge arrangements

The 25-pounder fired "separate"or two-part ammunition—the projectile and the propelling charge in its (usually brass) cartridge case with its integral primer were loaded separately. Typically for a quick-firing gun, the cartridge case provided obturation.

There were two types of cartridge. The "normal" cartridge contained three cloth charge bags (coloured red, white and blue). White or blue bags would be removed from the cartridge to give "charge one" or "charge two", leaving all three bags in the cartridge case gave "charge three". The cartridge case was closed at the top with a leatherboard cup. The second type of cartridge was "super", which provided one charge only. The cup could not be removed from the cartridge case. In 1943, an incremental charge of 5.5 oz (160 g) of cordite ("super-plus") was introduced to raise the muzzle velocity when firing AP shot with charge super; this required a muzzle brake to be fitted.^[2] Adoption of "upper-register" (high-angle) fire needed more charges to improve the range overlap. This led to the development of the "intermediate increment" of 4oz cordite, which was introduced in 1944. The bags were striped red and white to indicate that they should only be used with charges one and two. When one bag was used with charge 1 it provided charge 1/2. When one was added to charge 2 it provided charge 2 1/3, and two bags, charge 2 2/3. This allowed a range of seven different charges instead of four.^[3]

There were many marks of cartridge, mostly differentiated by propellant type. Double-base propellant (nitrocellulose/nitroglycerine) was the UK standard but one mark used US single-base (nitrocellulose only). However, triple-base nitrocellulose/nitroglycerine/picrite was used throughout the war and eventually replaced all others.^[4]

Display of 25-pounder shells and cases. Left to right: smoke, armour-piercing (pre-1955 UK markings), HE (RDX/TNT, strange markings), HE (Amatol, pre-1955 UK markings), smoke (pre-1955 UK markings). Although some shells are shown in the cases, the shell and the case were separate items.

The 25-pounder's main ammunition was the high-explosive (HE) streamlined shell with a 5/10 CRH ogive and boat tail. It was also provided with base ejection smoke (white and coloured), star shells, and chemical shells. Incendiary and coloured flare shells were developed but not introduced into service, and smoke shells were sometimes reloaded with propaganda leaflets or metal foil "window". The UK did not develop a WP smoke shell for the 25-pounder.

For anti-tank use, the 25-pounder was also supplied with a limited amount of 20 pounds (9.1 kg) solid armour-piercing (AP) shot, later replaced with a more potent version with a ballistic cap (APBC). The AP shot was fired with maximum charge, charge No. 3, super, or super with Super increment depending on the ordnance mark, as muzzle velocity was critical in direct fire for penetration and a flat trajectory.

A shaped charge anti-tank shell was under development in Canada, but the introduction of the QF 17 pounder, an anti-tank gun, in 1944 ended its development. After the Second World War, the UK replaced AP shot with a HESH shell. Coloured marker shells (dye and PETN) were also developed but not introduced.

The standard fuze was No 117 direct action (DA). No 119 (DA and graze) was also used. Combustion or mechanical time fuzes were used with base ejection shells and mechanical time with graze were used with HE. Proximity fuzes were used from the end of 1944 and subsequently replaced by CVT fuzes.

British service

An Australian 25-pounder at El Alamein in July 1942

The 25-pounder was the main field artillery weapon used by British Commonwealth and colonial infantry and armoured divisions of all types during the Second World War. It was also used by the RAF Regiment in North Africa.^[5] Throughout the war each British-pattern infantry division was established with 72 25-pounders, in three field artillery regiments (battalions). Armoured divisions eventually were standardised with two field artillery regiments, one of which was self-propelled (see below). Before mid-1940 each regiment had two batteries (companies) of twelve guns; after that date regiments changed to batteries of eight guns and added a third battery, a process that was not completed until early 1943. In the late 1950s, the British Army reverted to batteries of six guns. Field artillery regiments had two batteries of 25-pounders and one of 5.5 inch guns.

The early 18- and 25-pounders had been towed in the field by the Light Dragon, a tracked vehicle derived from a light tank, and the Morris CDSW. Throughout most of the Second World War the 25-pounder was normally towed, with its limber, behind a 4x4 field artillery tractor called a "quad". These were manufactured by Morris, Guy and Karrier in England, and, in greater numbers, as the Canadian Military Pattern field artillery tractor by Ford and Chevrolet in Canada. In the 1950s, the British Army replaced the various "quads" with a new Bedford three-ton gun tower fitted with a specialist body.

Gunner's view; 25-pounder on display at Edinburgh Castle

In 1941, the British Army improvised a self-propelled 25-pounder named the Bishop, on the chassis of the Valentine tank. This mount was unsatisfactory and was replaced in 1942 by the American M7 Priest. However, this complicated the supply of ammunition in the field, and was replaced in 1944 by the Sexton, which was designed and mostly manufactured in Canada (some 2/3 of ordnances and mountings were imported from the UK due to limited Canadian production capacity) and mounted the 25-pounder on a Ram or Grizzly tank chassis.

A 25-pounder of the ceremonial Gun Troop of the Bermuda Regiment

By World War II standards, the 25-pounder had a smaller calibre and lower shell-weight than many other field-artillery weapons, although it had longer range than most. (Most forces had entered the war with even smaller 75 mm (3.0 in) designs but had quickly moved to 105 mm (4.1 in) and larger weapons.) It was designed for the British practice of suppressive (neutralising) fire, not destructive fire that had proved illusory in the early years of World War I. Nevertheless, the 25-pounder was considered by all to be one of the best artillery pieces in use. The effects caused by the gun (and the speed at which the British artillery control system could respond) in the North-West Europe Campaign of 1944–1945 made many German soldiers believe that the British had secretly deployed an automatic 25-pounder.^[6]

In UK service from the 1960s most 25-pounders were replaced by the 105mm Abbot SPG, some by the Oto Melara 105mm pack howitzer, and the remainder by the 105mm L118 light gun. The last British military unit to fire the 25-pounder in its field role (as opposed to ceremonial use) was the Gun Troop of the Honourable Artillery Company on Salisbury Plain in 1992.

Service with other nations

A 25-pounder firing a blank at Royal Armouries Museum, Fort Nelson

In addition to Commonwealth and colonial forces other Second World War users included the free forces of France, Greece, Poland, Czechoslovakia, Netherlands, Belgium and Luxembourg. The first shot fired by US artillery against the German army in World War II was from a 25-pounder of the 34th Infantry division.^[7]

After the Second World War 25-pounders remained in service with many Commonwealth armies into the 1960s. They were used in Korea by British, Canadian and New Zealand regiments and in Malaya by British and Australian batteries. They also featured in wars on the Indian sub-continent and in the service of Israeli and other Middle Eastern armies.

South Africa

The gun was called G1 by the South African Defence Force. It was extensively used in the early stages of the South African Border War, including Operation Savannah. The G1 is still used in the ceremonial role.

Rhodesia

The Rhodesian Army used the weapon during the Bush War but by this stage the round could not penetrate enemy bunkers.

Sri Lanka

The 25-pounder 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.

Ireland

In 1949, 48 ex-British-Army Mark III 25-pounders were acquired by the Irish Defence Forces and were in service with the reserves until 2009, having been replaced in the army by the 105 mm Light Gun in 1981. The Irish Army maintains a six-gun ceremonial 25-pounder battery for use on state occasions.

India

The Indian Army employed the 25-pounder into the 1980s.

Luxembourg

Four Luxembourg 25 pounder guns rebarrelled to 105 mm and fitted with new sights for gun salutes.

The Luxembourg Army maintains a number of 25-pounder guns rebarrelled to 105 millimetres (4.1 in) and fitted with new sights for gun salutes.

Greece

The 25-pounder first entered service with Greek forces in North Africa during WWII. Three (I,II and III) field artillery regiments of 24 pieces were created in total as part of the Greek infantry brigades created. They saw significant action at El Alamein and Rimini. After the war the 25-pounder served as part of the Greek Army during the Greek Civil War. A total of 125 25-pounder guns were used by the Greek artillery during the civil war of 1946–1949, in various organizational schemes. After the civil war they were organized into seven independent regiments of 18 guns. Following Greece's entry into Nato in 1952 and the standardization on American calibres in 1953, the 25-pounders were not retired (unlike other models), but were reorganised as 13 battalions of eight guns in divisional artilleries. In 1957 the influx of American artillery pieces permitted an increase from 8 to 12 guns per battalion. In 1964 a total of 54 25-pdr guns were delivered from Greece to Cyprus, where they entered service with the Cyprus National Guard organized into four battalions of 12 guns (181, 182, 183 and 185) and one independent battery of six guns (184). They saw action during the Turkish invasion of the island in 1974. The 25-pounder remained in Greek Army service until 1992, when it were retired as part of the CFE agreement. The guns of the Cyprus National Guard remain in storage.

New Zealand

Twenty-five-pounder gun of the New Zealand Field Battery in Korea.

The 16th Field Regiment of the Royal New Zealand Artillery, equipped with 25-pounders, was formed to join the United Nations force in the Korean War.^[8]

Iraqi Kurdistan

A 2015 news report shows at least one 25-pounder in service with Kurdish Peshmerga forces, employed against ISIS positions in Mosul, Iraq.^[9]

Variants

Mark I

25-pounder field gun of 153rd Field Regiment (Leicestershire Yeomanry) during a practice shoot in the mountains near Tripoli in the Lebanon, 7 June 1943.

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-pounder". The Mark I was a 25-pounder barrel and breech in the modified jacket of an 18 pounder gun, as a 'loose liner'. The jacket provided the interface to the 18-pounder carriage. The earliest versions retained 18-pounder type elevation sights but later ones had Probert pattern calibrating sights on the right side of the saddle. The Mark IV P, carriage was a box trail, Mark V P, was a split trail. These conversions of the 18-pounder first entered British service in 1937. 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 India. This mark of 25-pounder was limited to charge 3 due to its 18-pounder carriage.

Mark II

25-pounder with a muzzle brake.

The Mark II, fitted to the Mark I carriage was the standard gun during World War II. 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. In 1942 a muzzle brake was fitted to the gun to eliminate the instability caused when firing the 20 lb AP shell with Charge Super at direct fire low elevation angles. To preserve the gun's balance on the trunnions a counterbalance weight was also fitted, just in front of the breech ring. The designation of the modified gun was not changed. Eventually all guns serving in Europe were so converted.

Mark II/I

In 1946 a programme was introduced to modify the gun's breech ring by morticing the rear corners. A corresponding modification was made to the rear corners of the breech block. This was to reduce the instances of cracking the ring.

Mark III

The Mark III ordnance was a Mark II with a modified receiver to prevent the rounds from slipping back out when loading at high angles. It was introduced in January 1944.

Mark III/I

This was a Mk III gun with the same modification to the ring and block as for the Mk II/I above'.

Mark IV

The Mark IV was identical to the Mark III/I, and featured the modified ring and a paired block from new.

Short, Mark I

Main article: Ordnance QF 25-pounder Short

A Short 25-pounder in New Guinea in 1944.

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. Weighing 1,315 kilograms (2,899 lb), it was around 315 kg (694 lb) lighter than the 25-pounder Mark II.

The "Baby" was intended for jungle warfare and was only used by Australian units in the South West Pacific theatre of World War II. The gun could be towed by a jeep or broken down into 13 sections and transported by air. During the New Guinea campaign the gun was manhandled up steep jungle tracks where trucks could not operate.