QF 12-pounder 12 cwt AA gun

Ordnance QF 12 pounder 12 cwt anti-aircraft gun
Ordnance QF 12 pounder 12 cwt anti-aircraft gun
	Mk I* on World War I AA traveling platform mounting
Type	Anti-aircraft gun
Place of origin	United Kingdom
Service history
In service	1914 - 1918 (as land AA gun)
Used by	UK; Kingdom of Italy; Empire of Japan
Wars	World War I; World War II
Production history
Designed	1893
Manufacturer	Elswick Ordnance Company; Vickers
Variants	Mk I, Mk II
Specifications
Barrel length	12 ft
Shell	Fixed or separate QF 12.5 lb (5.7 kg)
Calibre	3 inch (76.2 mm)
Breech	single-motion screw
Recoil	Hydro-spring, constant, 12 inch
Elevation	0° - 85°
Traverse	360°
Muzzle velocity	2,200 ft/s (670 m/s)
Maximum firing range	20,000 ft (6,100 m)

The 12 pounder 12 cwt anti-aircraft gun was borrowed for AA use from the QF 12 pounder 12 cwt coast defence gun with the addition of a modified cradle for higher elevation, a retaining catch for the cartridge, and an additional spring recuperator above the barrel and high-angle sights. Writers commonly refer to it simply as "12 pounder anti-aircraft gun". 12 cwt referred to the weight of the barrel and breech (12 x 112 lb = 1,344 lb) to differentiate it from other "12 pounder" guns.

History

When World War I began Britain had no anti-aircraft artillery and had given little thought to it. Hence in 1914 when Germany occupied parts of Belgium and northern France, it faced the risk of air attack, and various medium calibre guns were adapted to high-angle mountings, including the 12 pdr 12 cwt. All QF 12 pounder ammunition at the time was "Separate loading QF" i.e. the propellant came in a brass cartridge case with primer ready installed, but the shell was loaded separately. For anti-aircraft firing, fixed QF rounds were quickly developed i.e. with the shell already attached to the cartridge case. This allowed slightly faster loading.

Combat use

12 pdr 12 cwt gun in use as improvised anti-aircraft gun on garrison mounting, Gallipoli 1915

For home air defence the gun was typically mounted on a high-angle mounting with an additional spring recuperator above the barrel, on a 2-wheel towed traveling platform, 7 ft (2.1 m) x 5 ft 4 in (1.63 m) The 4 stabilising arms at the corners were swung out, rods at the ends screwed down to lift the platform off the wheels which were then removed and the platform lowered to the ground.^[2]

It was also deployed on static mountings to defend prominent targets such as dockyards.

While the gun was much lighter than the QF 3 inch 20 cwt dedicated AA gun, for anti-aircraft use it lacked its range and shell weight. Hence the 3 inch 20 cwt gun became the heavy AA gun of choice both on land and ships from 1914 to 1937. The 12 pdr 12 cwt also proved only marginally superior to the much lighter QF 13 pounder 9 cwt as a light AA gun. Comparison:^[3]-

Gun	m/v ft/s	Shell (lb)	Time to 5,000 ft (1,500 m) at 25° (seconds)	Time to 10,000 ft (3,000 m) at 40° (seconds)	Time to 15,000 ft (4,600 m) at 55° (seconds)	Max. height (ft)^[4]
13 pdr 9 cwt	1990	12.5	10.1	15.5	22.1	19,000
12 pdr 12 cwt	2200	12.5	9.1	14.1	19.1	20,000
3 inch 20 cwt 1914	2500	12.5	8.3	12.6	16.3	23,500
3 inch 20 cwt 1916	2000	16	9.2	13.7	18.8	22,000^[5]

At the end of World War I, 36 guns were still in service in the home air defense of Britain, 10 on the Western Front and 2 in Mesopotamia where it was typically mounted on river barges.^[6]

The gun remained in Royal Navy anti-aircraft use, in the form of the new Mk V version, on smaller ships in World War II because of its dual capability of both low and high angle firing.

Ammunition


Mk II & Mk III cartridges, 1914 - original separate QF	Mk IV Common Lyddite AA shell, 1914

Surviving examples

Notes and references

^ Hogg & Thurston 1972, Page 57 quotes 22,000 ft. The same publication quotes 22,000 on page 234
^ Hogg & Thurston 1972, Page 56
^ Routledge 1994, Page 9
^ Hogg & Thurston 1972, Page 234
^ Routledge 1994, Page 13
^ Routledge 1994, page 27

Bibliography

I.V.Hogg & L.F. Thurston, British Artillery Weapons & Artillery 1914-1918. London: Ian Allan, 1972. ISBN 978-0-7110-0381-1
Brigadier NW Routledge, History of the Royal Regiment of Artillery. Anti-Aircraft Artillery, 1914-55. London: Brassey's, 1994. ISBN 1-85753-099-3

External links

12-pdr (3"/40 (7.62 cm)) 12cwt QF Marks I, II and V

[1] Hogg & Thurston 1972, Page 57 quotes 22,000 ft. The same publication quotes 22,000 on page 234

[2] Hogg & Thurston 1972, Page 56

[3] Routledge 1994, Page 9

[4] Hogg & Thurston 1972, Page 234

[5] Routledge 1994, Page 13

[6] Routledge 1994, page 27

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v t e British Empire artillery of the First World War
Armoured vehicle guns	QF 3-pounder Vickers QF 6-pounder Hotchkiss QF 6-pounder 6 cwt
Infantry guns	1.59-inch breech-loading Vickers Q.F. gun, Mk II
Field artillery	BL 12-pounder 6 cwt QF 12-pounder 8 cwt QF 12-pounder 18 cwt QF 13-pounder BL 15-pounder BLC 15-pounder QF 15-pounder QF 18-pounder QF 4-inch gun Mk III BL 4-inch gun Mk VII QF 4.5-inch howitzer
Medium & heavy artillery	QF 4.7-inch gun BL 5-inch howitzer BL 5.4-inch howitzer BL 60-pounder gun BLC 6-inch siege gun BL 6-inch gun Mk VII BL 6-inch gun Mk XIX BL 6-inch 26 cwt howitzer BL 6-inch 30 cwt howitzer BL 8-inch howitzer Mk I – V BL 8-inch howitzer Mk VI – VIII
Siege artillery	BL 7.5-inch Mk III naval gun BL 9.2-inch howitzer BL 9.2-inch Mk X naval gun BL 12-inch howitzer BL 12-inch Mk X naval gun BL 15-inch howitzer
Mountain artillery	RML 2.5-inch mountain gun BL 10-pounder mountain gun BL 2.75-inch mountain gun QF 2.95-inch mountain gun QF 3.7-inch mountain howitzer
Mortars	Garland trench mortar 3-inch Stokes mortar Vickers 1.57-inch mortar 2-inch medium mortar Newton 6-inch mortar 9.45-inch Heavy Mortar
Smoke and chemical weapons	4-inch Stokes Mortar Livens Projector Livens Large Gallery Flame Projector
Anti-aircraft guns	QF 1-pounder pom-pom QF 2-pounder "pom-pom" Mk II 75 mm AA gun QF 12-pounder 12 cwt QF 13-pounder 6 cwt QF 13-pounder Mk IV QF 13-pounder 9 cwt QF 3-inch 20 cwt QF 18-pounder QF 4-inch Mk V
Coastal artillery	QF 12-pounder 12 cwt QF 4-inch naval gun Mk I – III BL 6-inch Mk VII naval gun BL 9.2-inch Mk IX – X naval gun RML 9-inch
Railway guns	BL 9.2-inch railway gun BL 12-inch railway gun BL 12-inch railway howitzer BL 14-inch railway gun