BL 6 inch Mk XII naval gun

BL 6 inch gun Mk XII
Starboard forward casemate gun on HMS Warspite after the Battle of Jutland
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1914 - 1945
Used by	British Empire
Wars	World War I World War II
Production history
Designer	Vickers
Designed	1913
Manufacturer	Vickers
Number built	463
Specifications
Weight	15,512 pounds (7,036 kg) barrel & breech^[1]
Barrel length	270 inches (6.858 m) bore (45 cal)^[2]

Shell	100 pounds (45.36 kg) Lyddite, Armour-piercing, Shrapnel^[3]
Calibre	6 inches (152.4 mm)
Recoil	Hydro-spring, 16.5 inches (420 mm)^[6]
Elevation	-7° - 30°^[7]
Muzzle velocity	2,825 feet per second (861 m/s)^[4]
Maximum range	19,660 metres (21,500 yd)^[5]

The BL 6 inch Gun Mark XII^[8] was a British 45 calibres naval gun which was mounted as primary armament on light cruisers and secondary armament on dreadnought battleships commissioned in the period 1914 - 1926, and remained in service on many warships until the end of World War II.

1 Design
2 Naval service
3 Notable actions
4 Ammunition
5 See also
6 Surviving examples
7 Notes and references
8 Bibliography
9 External links

Design

This was a high-velocity naval gun consisting of inner "A" tube, "A" tube, wound with successive layers of steel wire, with a jacket over the wire.^[9]

Naval service

It superseded the 45-calibres Mk VII gun and the longer 50-calibres Mk XI gun which had proved unwieldy in light cruisers due to its length, and was Britain's most modern 6-inch naval gun when World War I began.

Guns were mounted in the following ships :

Birmingham class light cruisers laid down 1912, commissioned 1914
Arethusa class light cruisers laid down 1912, commissioned 1914
C class light cruisers of 1914
M29 class monitors of 1915
Queen Elizabeth class battleships laid down 1912, commissioned 1915
Revenge class battleships laid down 1913, commissioned 1916
Destroyer leader Swift as re-gunned in 1917
Danae (or "D") class light cruisers completed 1918 - 1919
Monitors Raglan and Abercrombie from 1918
Emerald (or "E") class light cruisers laid down 1918, commissioned 1926

Notable actions

Ordinary Seaman John Henry Carless was posthumously awarded the Victoria Cross for heroism in serving his gun on HMS Caledon during the Second Battle of Heligoland Bight on 17 November 1917.

Ammunition

This gun generated a higher pressure in the chamber on firing compared to preceding 6-inch guns such as Mk VII and Mk XI. This necessitated use of special shells capable of withstanding a pressure of 20 tons per square inch on firing, which had "Q" suffixed to the name. World War I shells were marked "A.Q." denoting special 4 C.R.H. shells for this gun.^[1]

Surviving examples

On monitor HMS M33 at Portsmouth Historic Dockyard, UK
A gun from HMAS Adelaide at HMAS Cerberus naval base, Victoria, Australia

Notes and references

^ ^a ^b Handbook, 1917, Page 5
^ Handbook, 1917, Page 7
^ 100 lb shells : Treatise on Ammunition, 1915
^ 2,825 feet per second using 27 lb 2 oz cordite MD size 19 propellant was the figure used in range tables. New guns were quoted with a muzzle velocity of 2,845 feet per second. Handbook, 1917, Page 5
^ http://navalhistory.flixco.info/H/54676x53535/8330/a0.htm
^ Handbook, 1917, Page 6, 23-26
^ 30° elevation was possible with P.XIII mountings used on light cruisers; 20° elevation was possible on some P.VII* mountings used on light cruisers; 14° elevation was possible with P.IX mountings used on battleships; 15° was possible with P.VII mountings used on light cruisers. Handbook, 1917, Pages 5, 31, 41, Plates 6, 24, 35
^ Mark XII = Mark 12 : Britain denoted Marks (models) of guns with Roman numerals until after World War II. This was the twelfth model of British BL 6-inch gun.
^ Handbook, 1917, page 5, 6

Bibliography

Campbell, John (January 1984). Gray, Randal. ed. "British Naval Guns, 1880–1945, No. 12". Warship (29): 30–32.
"Handbook For The 6-inch Breech Loading Mark XII. Gun" G.21117/17. Admiralty, Gunnery Branch, 1917.

External links

Tony DiGiulian, British 6"/45 (15.2 cm) BL Mark XII and Mark XX

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 & light cruiser main armament	QF 12 pdr 18 cwt · QF 14 pounder · 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 & 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 D Depth charge · 7.5 inch howitzer

Landing guns	QF 12 pounder 8 cwt

British Commonwealth Naval weapons of the Second World War

Monitor guns	BL 15 inch

Capital ship main armament	BL 14 inch · BL 15 inch · BL 16 inch

Heavy cruiser main armament	BL 7.5 inch Mk VI · BL 8 inch Mk VIII

Secondary armament & light cruiser main armament	QF 4 inch Mk V · QF 4.5 inch · QF 5.25 inch · BL 6 inch Mk XII · BL 6 inch Mk XXII · BL 6 inch Mk XXIII

Minesweeper, Sloop, Corvette, Frigate & Destroyer armament	QF 6 pounder 10 cwt · QF 12 pdr 12 cwt Mk V · QF 4 inch Mk IV · BL 4 inch Mk IX · QF 4 inch Mk XIX · QF 4.5 inch · BL 4.7 inch Mk II · QF 4.7 inch Mk IX & XII · QF 4.7 inch Mk XI

Submarine guns	QF 12 pdr 12 cwt Mk V · QF 3 inch 20 cwt · QF 4 inch Mk XII & XXII

Anti-aircraft weapons	Unrotated Projectile · Holman Projector · 20 mm Oerlikon · QF 2 pounder "pom-pom" Mk VIII · 40 mm Bofors · QF 3 inch 20 cwt · QF 4 inch Mk V · QF 4 inch Mk XVI · QF 4.5 inch · QF 4.7 inch Mk VIII

Light weapons	.303 Lewis machine gun · .50 Vickers Mk III machine gun · QF 3 pounder Vickers

Torpedoes	21 inch Mk VII · 21 inch Mk VIII · 21 inch Mk X · 21 inch Mk XI · 24.5 inch Mk I

Mines

Anti-submarine weapons	Thornycroft depth charge thrower · Hedgehog · Squid

Small craft armament	Molins 6 pounder · Vickers K machine gun · 18 inch torpedo

Foreign-sourced weapons	3-inch 23 caliber gun (US) · 3-inch 50 caliber gun (US) · 4-inch 50 caliber Mark 9 gun (US) · 5-inch 51 caliber Mark 8 gun (US) · Y gun depth charge projector (US)