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[]

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[]

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

Notes[]

↑ 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[]

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 DiGiulian
↑ ^2.0 ^2.1 ^2.2 ^2.3 ^2.4 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[]

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

External links[]

Wikimedia Commons has media related to Category:BL 4 inch Mk VIII naval gun.

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

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The original article can be found at BL 4-inch Mk VIII naval gun and the edit history here.

[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] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 DiGiulian

[Handbook1913-2] 2.0 ^2.1 ^2.2 ^2.3 ^2.4 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]