Saturday 22 September 2018

25 Pounds of Death

Divisional artillery of most WWII belligerents was filled with several types of weapons. The Wehrmacht and the US Army combined light and heavy howitzers, while the Red Army also used guns. The only exception was Great Britain, who had only one type of divisional cannon: the 87.6 mm 25-pounder gun-howitzer.

Having analyzed the experience of WWI, the British military composed new requirements for a prospective field gun in 1919. This gun was going to replace two wartime artillery systems: the 83.4 mm 18-pounder and the 4.5" (114.3 mm) howitzer. The guns weren't bad on their own, but had their drawbacks. The 18-pounder had a high muzzle velocity, but a narrow range of elevation. The howitzer with a steep trajectory was a good counterpart to it. The new system would have to combine the advantaged of both systems: a gun-howitzer.

The Royal Artillery Committee was presented with two gun-howitzer projects in 1924: the 3.9" (100 mm) QF and 4.1" (105 mm) BL. The first variant had single piece ammunition, the second one used separate propellant. Both systems were rejected for not meeting the requirement for a range of 15,000 yards. In 1928, the director of  Royal Artillery J.H. Lewis proposed the 3.7" (94 mm) gun-howitzer, but it was also rejected. Only in October of 1933 did the British finally make a decision regarding the caliber of the prospective gun: 3.45" or 87.6 mm. A larger caliber made it impossible to modernize old 18-pounder guns to accept the new round. In February of 1938, the howitzer-style inch designation was replaced with the gun-style weight designation, and the 3.45" cannon became the 25-pounder. This indicated that it was to be a gun first and a howitzer second.

First try

The creation of the new weapon went the evolutionary route. Initially, it was decided to modernize the 18-pounder guns. Around 2000 of them were already in stock, both issued and in warehouses. The liner was replaced with a new one, with thinner, but more sturdy walls. The carriage was also modernized, and wooden wheels were replaced with rubber tyred ones. The range was much lower than what was required, only 11,800 yards, but economics beat tactical considerations. The new weapon was adopted in 1935 under the name Ordnance QF 25-pounder Mk.I. Official documents sometimes called it the 18/25-pounder to separate out the older models.

1422 old 18-pounders were rebuilt in 1937-1941. They were equipped with three types of carriage: the Mk.VP with split trails or the single trail Mk.IIITP and Mk.IVP. The Mk.IIITP was used with almost no changes compared to the initial carriage, and the Mk.IVP was developed by Vickers using the carriage of an export 105 mm howitzer as the basis. With this carriage, the gun breech didn't foul the trail at high elevations, but went through a cutout. The split trail carriage, designed  at the Royal Workshops at Woolwich, was introduced in 1937, and allowed for a much larger traverse angle: 50 degrees compared to the 9 degrees of the single trail guns. The elevation range was from -5 to +37.5 degrees, but only +15 degrees with joined trails.

18/15-pounder on a Mk.VP carriage.

A new 25-pounder

In parallel with the modernization of the 18-pounder, work on a new 25-pounder continued, designated the Mk.II. It was accepted into service in December of 1937, but put into production only in 1939. Before that, the factories were busy modernizing 18-pounders. The Ordnance QF 25-pounder Mk.II had a completely new barrel and breech design.

An interesting feature of the Mk.II was the introduction of a rotating platform. In combat position, the wheels of the carriage were placed upon the platform, which gave it the ability to rotate. On one hand, the weapon now took more time to put into position, on the other hand this feature allowed the carriage to keep the simple single mount. The Mk.II was equipped with a panoramic sight (No.7A, No.7C, or No.9) as well as a No.29 or No.41 telescopic sight for firing directly. The gun had a hydraulic recoil brake and a hydropneumatic return mechanism.

Three types of carriages were used by the Mk.II. One of them was the standard mount from the Mk.I (single trail with a bend), which limited the elevation between -5 and +40 degrees, and was used with the No.9 turning platform. The significantly lighter Mk.II carriage ("Indian pattern") was designed to be used in the jungle. Since its wheel base was smaller, a new smaller platform had to be developed, designated No.22.

The next evolutionary step was the alteration of the Mk.I carriage to work with the No.22 platform. This led to the introduction of the Mk.III carriage in 1944. A number of changes were made, increasing the gun elevation to 55 degrees. However, it was not possible to fire from the turning platform at this elevation, only from the ground. A three-trail carriage (like on the 2-pounder and the Soviet D-30 122 mm howitzer) was considered, but rejected due to complexity and weight.

In Great Britain, the Vickers company dealt with 25-pounder production, producing 12,253 units at their factories in Sheffield and Newcastle. In addition, the 25-pounder was produced in Canada and Australia (1315 units in total). Canadian made guns were chiefly used to arm the Sexton SPG. This production did not cover Canada's needs, and weapons were also imported from Great Britain.

Assembly of 25-pounder Mk.II guns in Sorel (Canada), 1941.

The only serious modification made during production (in 1942) was the introduction of a two-chamber Solothurn model muzzle brake, which was necessary to fire supercharged AP rounds. Guns with this muzzle brake were designated Mk.II/1. Australian guns were not equipped with muzzle brakes, as the issue of tank warfare was not as pressing in New Guinea and other Pacific islands as in North Africa.


Initially, the 25-pounder could fire the following ammunition:
  • Mk.ID HE filled with Amatol or, more rarely, TNT and RDX.
  • Mk.IT armour piercing tracer.
  • Mk.ID BE smoke.
New ammunition was introduced during the war, such as the Mk.IID HE round. An illumination round with a parachute that could burn for 25-30 seconds was adopted in 1943, and a calibration round that put out smoke (yellow, red, green, or blue) in 1944. Propaganda rounds filled with leaflets (converted from smoke shells) saw limited use in North Africa.

Ammunition for the Mk.II gun. Left to right: post-war smoke shell, AP shell, HE shell with TNT and RDX, HE shell with Amatol, wartime smoke shell. The first three shells are inserted into casings.

The shells could be fired with one of four propellant loads: 1st, 2nd, 3rd, or supercharged. The maximum range with the 1st load was 3566 meters, 7132 with the second, 10,790 with the third, and 12,253 with the supercharged. The 25-pounder's ammunition was half-QF: shells and propellant were stored and transported separately, but could be assembled before loading. The quick rate of fire was combined with a wide selection of propellants. In general, this scheme did not prevent a trained crew from achieving a high rate of fire. In one case, a 25-pounder crew from the 4th Royal Field Artillery Regiment fired 17 rounds in one minute.

The regular loadout for one gun was 142 rounds: 114 HE, 16 smoke, and 12 AP.

British field artillery

A tactical unit of British field artillery at the start of WWII was one two-battery regiment. Each battery contained 12 18/25-pounder guns split up into three platoons (regiments with old guns were equipped with one 4.5" howitzer platoon and two with 18-pounders). The regiment had 24 guns in total and was staffed with 580 men. The artillery regiment was fully motorized, with over 120 vehicles (plus nearly 30 motorcycles). This point is rarely stressed, but at the start of WWII Britain was the only army to have fully motorized its artillery. For the sake of tradition, regiments were separated into Royal Field Artillery Regiments and Royal Horse Artillery Regiments, but by the start of WWII their structures were identical. One infantry division had two or three artillery regiments, depending on the number of infantry brigades.

After the fighting in France in 1940, the field artillery regiments were reorganized. Instead of two batteries, they now had three, which better meshed with supporting three-battalion infantry brigades. Each battery was reduced to 8 guns (two platoons of four). The total number of guns in each regiment remained the same. The number of personnel increased to nearly 700.

The 25-pounder was crewed by 6 men:
  1. Commander
  2. Breech operator
  3. Gunner
  4. Loader
  5. Ammunition carrier
  6. Fuse setter
A late production Mk.II with a muzzle brake being installed on its turning platform. The limber and Quad truck are visible.

The main means of towing the 25-pounder gun were the 4x4 Quad trucks. They were pretty densely packed, and while the crew could fit inside comfortably, there was no room for ammunition. Single-axle limbers were used as a result: the pre-war No.24 and wartime No.27. Both could fit 32 shells and propellant casings, as well as instruments. The No.27 limber was lower, simpler to produce, and had a carrier for transporting the turning platform.

Use in battle

British artillery only began rearming when WWII began. Artillery regiments were only starting their familiarization with the 18/25-pounder guns, and the Mk.IIs have not yet arrived. Only 78 barrels were produced by September 1st, 1939, and not a single carriage. The British Expeditionary Force arrived in France with old 18-pounder guns and 4.5" howitzer alongside 18/25-pounders. 704 18/25-pounder guns were lost in France, partially destroyed and partially captured by the Germans. The Wehrmacht adopted them as the 8.76 cm feldkanone 281(e) for the guns on Mk.IVP carriages and 8.76 cm feldkanone 282(e) for guns on Mk.VP carriages. 334 guns were evacuated from the continent. It is not known what proportion of these were the Mk.I and what was composed of other guns.

An 18/25-pounder used by the BEF. The design of the limber with the rotating platform on top is visible.

British light artillery had the following numbers as of June of 1940:
  • 18-pounders: 126 in Britain and 130 in the colonies
  • 18/25-pounders: 269 in Britain and 146 in the colonies
  • 25-pounders: 90 in Britain (none in colonies)
The 25-pounder Mk.II began its career in battle in April of 1940 during the Norwegian campaign. The 203rd battery armed with these guns fought in Harstad, Mosjøen, Namsos, and Håkvik. 

A platoon of 25-pounders on exercises, Scotland, March 1941.

The finest hour of the Mk.II gun was the fighting in North Africa. Regiments armed with these guns deflected the Italian offensive in September-December of 1940. Alongside regular artillery duties, the guns could be used as anti-tank measures against thin-skinned Italian tanks. The appearance of the Africa Corps in Lybia made the artillerymen's life difficult. The PzIV could only be penetrated from a range of 350-400 meters. As a result of the campaign in 1942, the British decided that it was much more reasonable to fire indirectly at tank columns as they approach the front lines than try to use them as classic anti-tank guns.

Experience in Africa revealed the necessity in massed artillery fire. Earlier, the battery was considered a tactical unit, but by 1942 fire missions were designed for larger groups: from a regiment (24 guns) to the whole corps worth of artillery (150-250 guns). Concentrated indirect fire achieved impressive results. For example, a barrage by 25-pounders in April of 1942 against a group of 30 tanks led to the destruction of 5 and forced the others to retreat. The greatest concentration of artillery was at El-Alamein, where 834 guns took a part in the barrage on the night of October 22nd-23rd, 1942. The weapons were not only firing at the enemy positions, but at minefields and barbed wire. During the next 12 days, each gun fired an average of 102 rounds per day. On the night of November 1st-2nd, the concentration of 25-pounder guns in the sector of the 2nd New Zealand Division reached 52 guns per 1 kilometer (roughly one gun for every 19 meters of the front).

A 25-pounder Mk.II gun towed by a Quad truck, North Africa, December 1941.

During the campaign in Europe in 1944, the Canadian Sexton SPG was frequently used alongside towed guns. American 105 mm howitzers were rarely used, and most Priest SPGs equipped with this gun were converted into APCs. The British military had the opinion that the somewhat smaller destructive power of the 87.6 mm shell compared to its 105 mm counterpart is compensated by the rate of fire. German POWs even referred to 25-pounders as autocannons during interrogations.

The organization of artillery remained largely unchanged during the fighting in Western Europe. Each regiment received forward observer units, equipped with experienced officers, halftracks, and Universal Carriers. All HQs of infantry and tank units from the battalion level and higher had artillery signals officers, who were tasked with organizing fire support. All of this resulted in a high amount of ammunition consumption, but the Allies had ammo to spare. 72 guns of the 2nd Canadian Division fired 193,000 shells from July 20th to July 27th. Each gun fired 335 times per day on average.

A gun of the 5th Field Regiment of Royal Canadian Artillery, Netherlands, February 1st, 1945.

Polish artillery on exercises before landing in Normandy.

Alongside British formations, 25-pounder Mk.II guns were widespread in other Allied units: Free French, Anders' army, the Dutch, Belgian, and Greek forces. The first American division in Europe, the 34th Infantry, also received 25-pounder guns instead of 105 mm howitzers. The division trained with these weapons and went into battle with them in Africa in November of 1942, only replacing them with 105 mm howitzers at the end of the campaign in Tunisia. Command of the 21st Army Group gave the Americans 100 Mk.II guns and 300,000 rounds of ammunition to compensate for the losses taken during the fighting in the Ardennes. Captured 18/25-pounder guns were used by the Wehrmacht during fighting in France in 1944, and 25-pounders were standard equipment in Africa: reconnaissance battalions of the 15th and 21st Tank Divisions received four of these guns each instead of regular 75 mm guns.

The 2nd Infantry Division was one of the American units that received 25-pounders to compensate for losses taken in the Ardennes.

Preparing firing positions for a 25-pounder gun, Royal Australian Artillery, New Guinea, June 7th, 1945. Mk.II guns used in the Pacific were not equipped with muzzle brakes.

After the war, 25-pounder guns were used in Korea, Malaya, Egypt, and during a number of other conflicts. Regular British units kept using 25-pounders until 1967, and they were used for training into the 1980s. The last British unit to use these guns was the salute platoon of the Honourary Artillery Company, which disposed of them in 1992.

The New Zealanders and Canadians used the 25-pounder in Korea alongside the British. The photo shows a battery of the 2nd Canadian Horse Artillery Regiment. American 2.5 ton GMC trucks are used to tow the guns.

The Mk.II was widely used in other countries, primarily those that were formed after the collapse of the British Empire. These guns formed the backbone of Indian and Pakistani field artillery until the 1970s, and were used in all conflicts between these nations, as well as the border conflict between India and China in November of 1962.

The 25-pounder Mk.II was standardized as the G1 in the South African Republic and widely used in conflicts with its neighbours. The Rhodesian army used these guns during the Bush War.

Kurd units in North Iraq used these guns into the 21st century. At present, these guns are still used by Ireland (in reserve units) and the Cyprus National Guard. Many nations still use them as salute or ceremonial guns, from Fiji (four 25-pounders) to the Bermuda Islands (the Royal Bermuda Regiment's heavy weapons arsenal consists of two 25-pounders). 

25-pounders are often used for ceremonial purposes. This photo depicts the funeral of Lee Kuan Yew, the father of independent Singapore.

Original article by Andrei Haruk.

1 comment:

  1. Great article.

    I don't see much difference in rate of fire between a US 105mm howitzer and a 25 pounder. However, the 25 pounder has a range advantage that might be important, depending on what other assets are available. That's somewhat offset by the lower destructive effect of the 25 pounder's HE shell compared to the 105 though.