BL 4 inch naval gun Mk VII

Ordnance BL 4 inch gun Mk VII
On HMAS Australia, 1918
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1908 - 1945
Used by	United Kingdom
Production history
Number built	600
Specifications
Weight	4,704 pounds (2,130 kg) (barrel & breech)^[1]
Barrel length	201.25 inches (5.112 m) bore (50.3 calibres)^[1]

Shell	31 pounds (14.06 kg) Common pointed, Common lyddite^[1]
Calibre	4 inches (101.6 mm)
Breech	Welin, Single-motion screw^[1]
Muzzle velocity	2,852 feet per second (869 m/s)^[2]
Maximum firing range	11,600 yards (10,600 m) at 15°^[3]

The BL 4-inch gun Mk VII^{[note 1]} was a British high-velocity naval gun introduced in 1908 as an anti-torpedo boat gun in large ships, and in the main armament of smaller ships.^[1] It was also used as a defensive weapon on Defensively Equipped Merchant Ships (DEMS) during the Second World War.^[3]

Naval history

The guns armed the following warships :

Bellerophon-class battleships, laid down 1906
St. Vincent-class battleships, laid down 1907
Boadicea-class scout cruisers, laid down 1907
HMS Neptune, laid down 1909
Colossus-class battleships, laid down 1909
Indefatigable-class battlecruisers, laid down 1909
Orion-class battleships, laid down 1909
Lion-class battlecruisers, laid down 1909
Bristol-class light cruisers, laid down 1909
Blonde-class scout cruisers, laid down 1909
Active-class scout cruisers, laid down 1910
King George V-class battleships, laid down 1911

On a "DEMS" (defensively equipped merchant ship), 1943

The gun was succeeded in the "heavy" 4-inch class on new warships commissioned from 1914 onwards by the QF 4 inch Mk V. This new generation of warships were more heavily armed, and the BL Mk VII's role as secondary armament on capital ships and primary armament on cruisers was taken over by the BL 6 inch Mk VII and BL 6 inch Mk XII while the 4-inch calibre became the secondary armament on cruisers and primary armament on destroyers.

In World War II many guns were used to arm merchant ships.

World War I field gun service

East Africa, World War I

A battery of 4 guns mounted on field carriages was first deployed with the South African Heavy Artillery in the German South West Africa campaign in 1915 and returned to England in September. They were then deployed in the East African Campaign from February 1916 with 11th Heavy Battery (renumbered 15th Battery from April 1916) manned by the Royal Marine Artillery.^[4]

Image gallery

Barrel dimensions
Breech mechanism
Percussion and electric locks
Field carriage as depicted in 1913 manual

Surviving examples

Gun from HMS New Zealand outside the Auckland War Memorial Museum

2 Mk VII guns from HMS New Zealand outside the Auckland War Memorial Museum

Notes

↑ Mk VII = Mark 7. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. Mark VII indicates this was the seventh model of BL 4-inch gun.

References

1 2 3 4 5 HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913
↑ 2852 ft/second firing a 31 lb 3 C.R.H. projectile, using 9 lb 5 oz 15 drams cordite MD size 16 propellant. HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913.
1 2 Campbell, Warship Volume X, p. 53.
↑ Farndale 1988, page 318

Bibliography

HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913 (Corrected to September 1913.) ADMIRALTY Gunnery Branch, G.8652/13
Campbell, John (1987). Lambert, Andrew D., ed. "British Naval Guns, 1880–1945, No. 17". Warship 10: 53–55.
DiGiulian, Tony. British 4"/50 (10.2 cm) BL Mark VII
Farndale, General Sir Martin. History of the Royal Regiment of Artillery : Forgotten Fronts and the Home Base 1914-18. London:The Royal Artillery Institution, 1988

External links

Wikimedia Commons has media related to BL 4 inch Mk VII naval gun.

British Empire naval weapons of the First World War

Monitor guns	BL 9.2 inch Mk VI BL 9.2 inch Mk VIII BL 9.2 inch Mk X BL 9.2 inch Mk XII BL 12 inch Mk VIII US 14 inch 45 cal BL 18 inch Mk I

Capital ship main armament	Vickers 10 inch 45 cal EOC 10 inch 45 cal BL 12 inch Mk VIII BL 12 inch Mk IX BL 12 inch Mk X BL 12 inch Mk XI & XII EOC 12 inch 45 cal Mk XIII BL 13.5 inch Mk V EOC 14 inch 45 cal Mk I BL 15 inch Mk I

Armoured cruiser main armament	BL 7.5 inch Mk I BL 9.2 inch Mk X BL 9.2 inch Mk XI

Secondary armament and light cruiser main armament	QF 12 pdr 18 cwt QF 14 pounder Maxim-Nordenfelt QF 14 pounder Mk I & II QF 4 inch Mk III BL 4 inch Mk VII QF 4 inch Mk V BL 4 inch Mk IX BL 5.5 inch Mk I QF 6 inch BL 6 inch Mk VII BL 6 inch Mk XI BL 6 inch Mk XII BL 6 inch Mk XIII-XVIII BL 7.5 inch Mk II - Mk V

Destroyer and small cruiser armament	QF 12 pdr 12 cwt Mk II QF 4 inch Mk III BL 4 inch Mk VIII QF 4 inch Mk IV BL 4.7 inch Mk I

Merchant ship armament	QF 4.7 inch Mk I - IV QF 4.7 inch Mk V*

Submarine guns	BL 4 inch Mk XI QF 4 inch Mk XII

Anti-aircraft guns	QF 2 pounder "pom-pom" Mk II QF 3 inch 20 cwt QF 4 inch Mk V

Light weapons	.303 Vickers machine gun QF 3 pounder Hotchkiss QF 3 pounder Vickers QF 6 pounder Hotchkiss

Torpedoes	18 inch Mk V - VIII 21 inch Mk II 21 inch Mk IV

Mines	Spherical Mk I, II and III Vickers Elia mine Type H mine

Anti-submarine weapons	Type A Depth charge Type B Depth charge Type C Depth charge Type D Depth charge Type E Depth charge Type F Depth charge Type G Depth charge Cruiser Mine 7.5 inch howitzer

Landing guns	QF 12 pounder 8 cwt

British Empire Small Arms & Ordnance of the First World War

No. 1
No. 2 Hales Pattern
Nos. 3, 20, 24, 35 Hales rifle grenades
Nos. 5, 23, 36 Mills
No. 6
Nos. 8, 9 Jam Tin
No. 13 Battye
No. 14 Pitcher
No. 15 Ball
No. 16 Oval
No. 17 Opera hat
No. 18
No. 19
No. 21 "Spherical"
No. 22 Newton-Pippin
No. 25 Sangster
No. 27
No. 28 Chemical
No. 29 Gas
No. 31 Day Signal
No. 32 Night Signal
No. 32 "Spherical E"
No. 34 Egg
No. 37
No. 39 Steuart Pattern

Artillery

Tank guns	QF 6 pounder Hotchkiss QF 6 pounder 6 cwt

Infantry guns	1.59-inch Breech-Loading Vickers Q.F. Gun, Mk II ("Vickers-Crayford rocket gun")

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

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

Howitzers, medium, and 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

Coastal artillery	QF 4 inch naval gun Mk I – III BL 6 inch Mk VII naval gun BL 9.2 inch gun Mk IX–X RML 9 inch

Mortars

Grenade launchers

Smoke and chemical weapons

Railway guns

Anti-aircraft guns

Foreign weapon designs
in British Empire Armies use

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