BL 4-inch Mk VIII naval gun

Ordnance BL-4-inch Mk VIII naval gun
Ordnance BL-4-inch Mk VIII naval gun
	Forward gun of HMS Defender
Type	Naval gun
Service history
In service	1908–1945
Used by	United Kingdom; Australia
Wars	World War I – World War II
Production history
Designed	1904
No. built	Mk VIII: 246; Mk XI: 30
Variants	Mk VIII – Mk XI
Specifications
Mass	2,912 pounds (1,320 kg) (barrel & breech)
Barrel length	159.2 inches (4.044 m) bore (40 calibres)
Shell	31 pounds (14.06 kg) Common pointed, Common lyddite
Calibre	4 inches (101.6 mm)
Breech	Welin, single-motion screw
Elevation	-10° to +20°
Rate of fire	6-8 RPM
Muzzle velocity	2,287 feet per second (697 m/s)
Maximum firing range	10,210 yards (9,340 m)

The BL 4-inch Mark VIII naval gun^{[note 1]} was a British medium-velocity wire-wound naval gun introduced in 1908 as an anti-torpedo boat gun in smaller ships whose decks could not support the strain of the heavier and more powerful Mk VII gun.^[2]

Mk VIII history[edit]

The gun succeeded the QF 4-inch Mk III, whose 25-pound (11 kg) shell had been considered insufficiently powerful for its intended role. The BL Mk VIII fired a 31-pound (14 kg) shell. It armed the following warships :

HMS Swift laid down 1905
Tribal-class destroyers from HMS Saracen (1908) onwards.
Beagle-class destroyer of 1909
Acorn-class destroyers of 1910
Acheron-class destroyers of 1910
River-class torpedo-boat destroyers (Australia) of 1910.

The gun was succeeded in its class from 1911 by the QF 4-inch Mk IV.

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

Mk XI submarine gun[edit]

A Mark XI-variant was adapted to arm the K-class submarines laid down 1915.

Notes[edit]

^ Mark VIII = Mark 8. Mark XI = Mark 11. Britain used Roman numerals to denote marks (models) of ordnance until after World War II. This was the eighth model of British BL 4-inch gun.

References[edit]

^ ^a ^b ^c ^d ^e ^f DiGiulian
^ ^a ^b ^c ^d ^e HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913
^ 2287 ft/second firing a 31 lb 3 CRH projectile, using 5 lb 4 oz cordite MD size 16 propellant. HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913.

Sources[edit]

HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913 (Corrected to September 1913.) ADMIRALTY Gunnery Branch, G.8652/13

External links[edit]

Tony DiGiulian, British 4"/40 (10.2 cm) BL Mark VIII and Mark XI

[4] Mark VIII = Mark 8. Mark XI = Mark 11. Britain used Roman numerals to denote marks (models) of ordnance until after World War II. This was the eighth model of British BL 4-inch gun.

[DiGiulian-1] ^ ^a ^b ^c ^d ^e ^f DiGiulian

[Handbook1913-2] HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913

[3] 2287 ft/second firing a 31 lb 3 CRH projectile, using 5 lb 4 oz cordite MD size 16 propellant. HANDBOOK for the 4" Mark VII. and VIII. B.L. Guns 1913.

[1]

[2]

[3]

[note 1]

v t e 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 BL 14-inch Mk II (US built) BL 15-inch Mk I 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 I – IV BL 13.5-inch Mk V BL 13.5-inch Mk VI 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-pounder 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 Mk I – III 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-pounder 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