By Lasse Jensen

Last updated 18 Marts 2002

Royal Ordnance Quick Fire 25 pounder Mark I
 

General


Designer


25 pounder Mark 1 on 18 pdr Mark 4p carriage
(p for pneumatic tires)
Original Manufacture Royal Ordnance, England
Original Manufacture name Ordnance 3.45 inch
Is this a license build gun? no
License Manufacture ~
Customer Aim Domestic military
Prototype naming Ordnance 3.45 inch
Indented country naming England, 25 pounder Mark 1
Naming variants England - '18/25 pdr'
Germany -'8.76cm FK 281(e)'
reversion models none
Licenses build variants none
Export variants none
Nature of weapon Field gun-howitzer
Introduction date 1938
First action date Norway, April 1940
Production time 1936-1939
Production number +12000 (all versions)
Crew

Gun dimension

Caliber, bore 87.63mm (3.45inch)

Caliber, length/bore
Muzzle brake no
Recoil system
Breech mechanism
Barrel length (all) 
Barrel length (ex breech)
Barrel weight (all)
Weight (firing position) 1625 Kg
Weight (traveling order)
Length (firing position)
Length (traveling order)
Width (firing position)
Width (traveling order)
Height (firing position)
Height (traveling order)
Ground Clearance (towing)

Gun performers

    

Traverse Right 360° w/ firing platform, 4° without
Traverse Left 360° w/ firing platform, 4° without
Elevation +37.5°
Depression -5°
Ammunition types 11.34 Kg -HE
9.89 Kg -smoke
Maximum Range 10.515m -HE
Muzzle velocity 198m/s -smoke
297m/s -HE
Rate of Fire - 30s ~3-4 rounds
Rate of Fire - 4m ~15-25 rounds
Rate of Fire - 10m ~25-40 rounds
Rate of Fire - 1h, sustained ~80 rounds

Carriage

    

Name 18 pdr carriage Mark 4
Variants Mark 4P, Mark 5, Mark 5P
Shield yes
Weight
Wheels (if any) yes
Tyres (if any) yes on Mark 4P-5P, unknown type

Towing vehicle

    

Primary type Field Artillery Tractor (FAT)
Trailer artillery trailer no 27

 

History
As the 18pdr Mark 4, in the 1920s, was not deemed suitable for further development, an entirely new equipment was proposed. Royal Artillery experts had concluded that a gun of around 3.7 inches (94 mm) in caliber with a range of at least 15.000 yards (13.716 m) firing a shell of from 20 to 25 lbs (9 to 11 kg) weight was needed to replace both the old 18 Pounder and QF 4.5 inch howitzer.

Experiments with an 18pdr, a 22pdr, and a 25pdr were carried out in 1933, and in the same year the General Staff agreed a 25pdr be the sole field artillery equipment. In 1934, after further discussion with the War Department on specifications, the Director of Artillery (United Kingdom) ordered a pilot model.

Then arose the specter of what has forever been the bane of the British soldier in peacetime - a tight-fisted Treasury. The holders of the purse-strings decreed that if the Gunners wanted a new field gun they would have to convert the existing Mark 4 18pdrs of which there were large stocks. Now the Mark 4 18pdr, caliber 3.3 inches (84 mm), was fitted with a loose liner which could be easily removed and replaced, so at first sight conversion appeared simple; change the liner to one of larger caliber. However, 3.45 inches (87.6 mm) was the maximum to which the gun could be re-lined and at the same time retain an adequate margin of safety. So in 1935 it was officially decided to adopt a 25pdr of 3.45-in caliber. This was the 25pdr Mark 1, often referred to as the '18/25pdr', indicating conversion. Gunners who served in France and in the Middle East in the very early days of World War 2 will be familiar with it.

There was another snag: the 18pdr carriage would not stand a propellant charge powerful enough to send a 25pdr shell the desired 15.000 yards, ie it could not fire super. Consequently, a maximum range of 11.800 yards had to be accepted. About a year later, in 1936, a decision to increase the range to 13.500 yards carried with it approval to design a new equipment capable of firing super charge, which was the Mark 2.

Numbers along the Mark 2 first saw service in Norway 1940.

It was one of the first weapons designed as a gun / howitzer combining the best features of these weapon types. It uses variable charges allowing it the ability to fire its projectiles in a high arc similar to a howitzer but also may fire at high velocities for a flat trajectory. During the fighting in North Africa during 1941-42 it was pressed into use as an anti-tank weapon where it proved itself in that role as well.
More Pictures
MK1 on 18pdr MK 4p MK1 on 18pdr MK 4p w/ trailer no. 27      
     
Unknown location Unknown location      

References: 
The Story of the Twenty-five Pounder by WL Ruffell
Additional web resources.
Various web notes.

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