QF 2 pounder naval gun
Encyclopedia
The 2-pounder gun, officially designated the QF 2-pounder (QF denoting "quick firing") and universally known as the pom-pom, was a 1.575 inch (40 mm) British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 autocannon
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...

, used famously as an anti-aircraft gun
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...

 by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. The name came from the sound that the original models make when firing. Although these were 2-pounder guns, in that they fired a projectile with a weight of 2 pounds
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

, they were not the same gun as that used by the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 as an anti-tank weapon or to equip British tanks and certain armoured cars.

QF 1 pounder

The first gun to be called a pom-pom was the 37 mm Nordenfelt-Maxim
QF 1 pounder pom-pom
The QF 1 pounder, universally known as the pom-pom, was an early 37 mm British autocannon. It was used by several countries initially as an infantry gun and later as a light anti-aircraft gun. The name comes from the sound it makes when firing....

 or "QF 1-pounder" introduced during the Second Boer War
Second Boer War
The Second Boer War was fought from 11 October 1899 until 31 May 1902 between the British Empire and the Afrikaans-speaking Dutch settlers of two independent Boer republics, the South African Republic and the Orange Free State...

, the smallest artillery piece of that war. It fired a shell one pound in weight accurately over a distance of 3000 yards (2,743.2 m). The barrel was water-cooled, and the shells were belt-fed from a 25-round fabric belt. The Boer
Boer
Boer is the Dutch and Afrikaans word for farmer, which came to denote the descendants of the Dutch-speaking settlers of the eastern Cape frontier in Southern Africa during the 18th century, as well as those who left the Cape Colony during the 19th century to settle in the Orange Free State,...

s used them against the British, who, seeing their utility, had the design copied by Vickers
Vickers
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

, who were already producing Maxim gun
Maxim gun
The Maxim gun was the first self-powered machine gun, invented by the American-born British inventor Sir Hiram Maxim in 1884. It has been called "the weapon most associated with [British] imperial conquest".-Functionality:...

s.

In World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 it was used in the trenches of the Western Front
Western Front (World War I)
Following the outbreak of World War I in 1914, the German Army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne...

 against aircraft.

QF 1½ pounder

The first naval pom-pom was the QF 1.5-pdr Mark I, a piece with a calibre of 37 mm (1.46 in) and a barrel 43 calibre
Caliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....

s long. This was trialed in the Arethusa class
Arethusa class cruiser (1913)
The Arethusa-class cruisers were a class of eight oil-fired light cruisers of the Royal Navy all ordered in September 1912, primarily for service in the North Sea. They had three funnels with the middle one somewhat larger in diameter than the others. All served in World War I...

 light cruiser
Light cruiser
A light cruiser is a type of small- or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck...

s HMS Arethusa
HMS Arethusa (1913)
HMS Arethusa was the name ship of the Arethusa class of light cruisers. She was laid down at Chatham Dockyard in October 1912, launched on 25 October 1913, and commissioned in August 1914 as flotilla leader for the Harwich Destroyer flotillas....

 and HMS Undaunted
HMS Undaunted (1914)
HMS Undaunted was an Arethusa-class light cruiser of the Royal Navy launched on 28 April 1914 at Fairfield Shipbuilding and Engineering Company's shipyard at Govan.Undaunted participated in numerous naval operations during the First World War...

, but did not enter full service, being replaced instead by a larger weapon, the QF 2-pdr Mark II (see below).

QF 2-pounder Mark II

The QF 2-pounder Mark II was essentially a scaled-up version of the QF 1 pounder
QF 1 pounder pom-pom
The QF 1 pounder, universally known as the pom-pom, was an early 37 mm British autocannon. It was used by several countries initially as an infantry gun and later as a light anti-aircraft gun. The name comes from the sound it makes when firing....

 Maxim gun produced by Vickers
Vickers
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

. It was a 40 mm calibre gun with a water-cooled barrel and a Vickers-Maxim mechanism. It was ordered in 1915 by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 as an anti-aircraft weapon for ships of cruiser size and below. The original models fired from hand-loaded fabric belts, although these were later replaced by steel-link belts. This 'scaling-up' process was not entirely successful, as it left the mechanism rather light and prone to faults such as rounds falling out of the belts.

Surviving weapons were brought out of storage to see service in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, mainly on board second-rate ships such as naval trawler
Naval trawler
A naval trawler is a vessel built along the lines of a fishing trawler but fitted out for naval purposes. Naval trawlers were widely used during the First and Second world wars. Fishing trawlers were particularly suited for many naval requirements because they were robust boats designed to work...

s, Motor Boats and "armed yachts". It was used almost exclusively in the single-barrel, unpowered pedestal mountings P Mark II (Royal Navy nomenclature gave mountings and guns their own distinct Mark numbers) except for a small number of weapons on the mounting Mark XV, which was a twin-barreled, powered mount. These were too heavy to be of any use at sea, and were therefore mounted ashore. All were scrapped by 1944.
  • Calibre: 40 mm L/39
  • Total length: 96 inches.
  • Length of bore: 62 inches
  • Rifling: Polygroove, plain section, 54.84 inches, uniform twist 1 in 30 inch, 12 grooves.
  • Weight of gun & breech assembly: 527 lb
  • Shell Weight: 2 lb (980 g). HE.
  • Rate of Fire: 200 rpm
  • Effective Range: 1,200 yd (1,000 m)
  • Muzzle Velocity: 1920 ft/s (585 m/s)


Some 7,000 guns were made. The gun was also used by the Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese as the 40 mm/62 "HI" Shiki.

QF 2-pounder Mark VIII

The Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 had identified the need for a rapid-firing, multi-barrelled close-range anti-aircraft weapon at an early stage. Design work for such a weapon began in 1923 based on the earlier Mark II, undoubtedly to utilise the enormous stocks of 2-pounder ammunition left over from World War I. Lack of funding led to a convoluted and drawn-out design and trials history, and it was not until 1930 that these weapons began to enter service. Known as the QF 2-pounder Mark VIII, it is usually referred to as the multiple pom-pom. The initial mounting was the 11.8 to 17.35 ton, eight-barrelled mounting Mark V (later Mark VI), suitable for ships of cruiser
Cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...

 and aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

 size upwards. From 1935 the quadruple mounting Mark VII, essentially half a Mark V or VI, entered service for ships of destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

 and cruiser
Cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...

 size. These multiple gun mounts required four different guns and were nicknamed the "Chicago Piano". The mount had 2 rows each of 2 or 4 weapons. Guns were produced in both right- and left-hand and "inner" and "outer" so that the feed and ejector mechanisms matched. Single-barrelled mounts, the Mark VIII (manual) and Mark XVI (power operated), were also widely used, mainly in small escorts (such as the 'Flower' Class corvettes
Flower class corvette
The Flower-class corvette was a class of 267 corvettes used during World War II, specifically with the Allied navies as anti-submarine convoy escorts during the Battle of the Atlantic...

) and coastal craft (especially early Fairmile 'D' motor gunboat
Motor Gun Boat
Motor Gun Boat was a Royal Navy term for a small military vessel of the Second World War. They were physically similar to the Motor Torpedo Boats but equipped with a mix of guns instead of torpedoes. Their small size and high speed made them difficult targets for E-boats or torpedo bombers, but...

s). The Mark XVI mounting was related to the twin mounting Mark V for the Oerlikon 20 mm cannon
Oerlikon 20 mm cannon
The Oerlikon 20 mm cannon is a series of autocannons, based on an original design by Reinhold Becker of Germany, very early in World War I, and widely produced by Oerlikon Contraves and others...

 and the "Boffin" mounting for the Bofors 40 mm gun
Bofors 40 mm gun
The Bofors 40 mm gun is an anti-aircraft autocannon designed by the Swedish defence firm of Bofors Defence...

. An interesting feature was the very large magazine, from 140 rounds per gun for the 8-barrelled mount, to 56 rounds for the single mounts. This large ammunition capacity gave the 8-barrelled mount the ability to fire continuously for 73 seconds without reloading.

The pom-pom and the USN

The United States Navy also considered adopting the pom-pom gun prior to its entry into World War II, and conducted a series of trials between the USN 1.1" gun, the US Army 37mm Gun
37mm Gun M1
The 37mm Gun M1 was an anti-aircraft autocannon developed in the United States. It was used by the US Army in World War II.In addition to the towed variant, the gun was mounted, with two M2 machine guns, on the M2/M3 half-track, resulting in the T28/T28E1/M15/M15A1 series of multiple gun motor...

, the Vickers 40mm pom-pom, and the Bofors 40 mm:
"Among the machine guns under consideration were the Army's 37-mm and the British Navy's 2-pounder, more commonly known as the "pompom." The decision soon narrowed to a choice between the Bofors and the British gun. The British were anxious to have their gun adopted, and the fact that British aid would be readily available in initiating manufacture was put forward as an argument in favor of its selection. The 2-pounder, moreover was giving a good account of itself on British ships. On the other hand, there was the distinct disadvantage that the gun was designed for cordite powder, and no manufacturing facilities for the production of this ammunition were available in the United States. Thorough study revealed that the gun could not be converted to take American powder. Another consideration was muzzle velocity: The pompom had a relatively low velocity, 2350 feet per second as compared with 2830 for the Bofors. The success of the pompom in action was more than offset by the proved qualities of the Bofors in the hands of a number of powers who were using it, and the Bureau decided to join that group. Shortly after the Bureau's selection of the Bofors, British naval officials also decided to adopt the gun."

Wartime use

An advanced weapon when introduced, by the outbreak of World War II advances in aircraft would have made it obsolete but for the introduction of a high-velocity round and new director designs. It was intended that the curtain of fire it threw up would be sufficient to deter attacking aircraft, which it did, but was hampered by the ineffective Mk III director. The MK IV Director
Pom-Pom Director
-History:The Vickers 40mm "Pom-Pom" Antiaircraft mounting was introduced to the Royal Navy in the early 1930s. The mounting was capable of a tremendous volume of fire but the crew had great difficulty in aiming the mounting due to the smoke and vibration created by the guns...

 with a Gyro Rate Unit
Gyro Rate Unit
-History:The Royal Navy, after World War I, became increasingly concerned with the threat posed by aerial attack. In 1930 the RN began equipping ships with the High Angle Control System, a non-tachymetric anti-aircraft fire control system, that would compute the gun laying orders and the time fuze...

 and Type 282 radar was a great advance and was introduced on the KGV class battleship
King George V class battleship (1939)
The King George V-class battleships were the most modern British battleships used during World War II. Five ships of this class were built and commissioned: King George V , Prince of Wales , Duke of York , Howe , and Anson .The Washington Naval Treaty of 1922 limiting all of the number,...

s. In January 1941, HMS Illustrious's Mk VIII (HV) mountings performed flawlessly firing 30,000 rounds with very few stoppages. When HMS Prince of Wales
HMS Prince of Wales (1939)
HMS Prince of Wales was a King George V-class battleship of the Royal Navy, built at the Cammell Laird shipyard in Birkenhead, England...

 was attacked and sunk by Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese aircraft near Singapore, the subsequent report judged that a single 40 mm Bofors
Bofors 40 mm gun
The Bofors 40 mm gun is an anti-aircraft autocannon designed by the Swedish defence firm of Bofors Defence...

 gun firing tracer was a more effective anti-aircraft weapon than a multiple pom-pom in director control, as the pom-poms did not have tracer ammunition and the pom-pom ammunition had deteriorated badly in their ready use lockers, while the Type 282 radar units also failed in the equatorial heat. In the same action, the Commissioned Gunner of HMS Repulse
HMS Repulse (1916)
HMS Repulse was a Renown-class battlecruiser of the Royal Navy built during the First World War. She was originally laid down as an improved version of the s. Her construction was suspended on the outbreak of war on the grounds she would not be ready in a timely manner...

 spent the whole action running from one pom-pom mount to another trying to keep them operational due to the faulty ammunition. The pom-poms on Repulse shot down 2 of the four confirmed kills made by Force Z, while Prince of Wales' pom-poms did record hits on enemy aircraft. The Royal Navy judged the pom-pom's effectiveness to range from about half that of the Bofors, per gun, against torpedo planes to about equal against Kamikaze attackers. It was a ubiquitous weapon that outnumbered the Bofors gun, in Commonwealth naval service, up to the end of World War II and shot down many Axis aircraft. Later innovations such as Remote Power Control (RPC) coupled to a radar-equipped tachymetric (speed predicting) director increased the accuracy enormously and problems with the fuses and reliability were also remedied. The single mountings received a reprieve towards the end of the war as the 20 mm Oerlikon guns had insufficient stopping power
Stopping power
Stopping power is a colloquial term used to describe the ability of a firearm or other weapon to cause a penetrating ballistic injury to a target, human or animal, sufficient to incapacitate the target where it stands....

 to counter Japanese Kamikaze
Kamikaze
The were suicide attacks by military aviators from the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, designed to destroy as many warships as possible....

 aircraft and there were insufficient numbers of Bofors guns to go round.
  • Calibre: 40 mm L/39
  • Shell Weight: 2 lb. (980 g) or 1.8 lb. (820 g) for High-Velocity (HV) round
  • Rate of Fire: 115 rpm fully automatic
  • Effective Range: 3,800 yards (3,475 m) or 5,000 yards (4,572 m) HV
  • Effective Ceiling (HV): 13,300 feet (3,960 m)
  • Muzzle Velocity: 2,040 ft/s (622 m/s) or 2400 ft/s (732 m/s) for HV


For more extensive technical data see 2-pdr Mark VIII at Navweaps.com

QF 2-pounder Mark XIV

The QF 2-pounder Mark XIV, or Rolls 2 pounder, was developed by Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....

 as a competitor to the 40 mm "Vickers S" gun
Vickers S
The Vickers Class "S" was a 40 mm cannon used to arm British aircraft for attacking ground targets in the Second World War.-History:...

 as an aircraft weapon. The latter was the more successful design, and found some use as an anti-tank weapon. A reworked version was adopted by the Royal Navy as a weapon for Motor Gun Boat
Motor Gun Boat
Motor Gun Boat was a Royal Navy term for a small military vessel of the Second World War. They were physically similar to the Motor Torpedo Boats but equipped with a mix of guns instead of torpedoes. Their small size and high speed made them difficult targets for E-boats or torpedo bombers, but...

s, being adopted in the Fairmile C
Fairmile C motor gun boat
The Fairmile C motor gun boat was a type of Motor Gun Boat designed by Norman Hart of Fairmile Marine for the Royal Navy. An intermediate design, twenty-four boats were built in 1941 receiving the designations MGB 312 - 335.-Design:...

 type. It had a semi-automatic horizontally sliding breech block
Breech-loading weapon
A breech-loading weapon is a firearm in which the cartridge or shell is inserted or loaded into a chamber integral to the rear portion of a barrel....

, and was shipped on a manually trained pedestal mount. The weapon was not a success, and of the 1,200 ordered only some 600 were delivered. It was replaced by the Molins 6-pounder gun, the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

's Ordnance QF 6 pounder gun (57 mm) with an auto-loader.

See also

  • QF 1 pounder pom-pom
    QF 1 pounder pom-pom
    The QF 1 pounder, universally known as the pom-pom, was an early 37 mm British autocannon. It was used by several countries initially as an infantry gun and later as a light anti-aircraft gun. The name comes from the sound it makes when firing....

  • List of anti-aircraft guns
  • British standard ordnance weights and measurements
    British standard ordnance weights and measurements
    The British standard ordnance weights and measurements for the artillery were established by the Master General of Ordnance in 1764, and these were not altered until 1919 when the metric system was additionally introduced....


External links

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