The BL 6-inch Mark XII naval gun was a British 45

calibre In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore match ...

naval gun Naval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for shore bombardment and anti-aircraft roles. The term generally refers to tube-launched projectile-firing weapons and excludes ...

which was mounted as primary armament on

light cruiser A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to th ...

s and secondary armament on

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s commissioned in the period 1914–1926, and remained in service on many warships until the end of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

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.

Naval service

HMS Enterprise 6-inch gun clip 1936 LOC matpc 20251

HMS Enterprise 1936 twin 6 inch gun turret LOC matpc 20229

HMS Malaya 6 inch casemate gun cre 1943 IWM A 16964

It superseded the 45-calibres Mk VII gun and the longer 50-calibres Mk XI gun which had proved unwieldy in light cruisers due to its length, and was Britain's most modern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 World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

began. It was superseded as secondary armament on new battleships in the 1920s by the 50-calibre 6-inch Mk XXII gun, and as main armament on new light cruisers in the 1930s by the 50-calibre 6-inch Mk XXIII gun. 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 HMS ''Swift'' as re-gunned in 1917 * ''Danae''-class (or D-class) light cruisers completed 1918–1919 * Monitors HMS ''Raglan'' and HMS ''Abercrombie'' from 1918 * ''Emerald''-class (or E-class) light cruisers laid down 1918, commissioned 1926

Coast defence gun

During WWII some Mk XII guns were used in emergency coast defense batteries.

Notable actions

* Ordinary Seaman John Henry Carless was posthumously awarded the

Victoria Cross The Victoria Cross (VC) is the highest and most prestigious award of the British honours system. It is awarded for valour "in the presence of the enemy" to members of the British Armed Forces and may be awarded posthumously. It was previously ...

for heroism in serving his gun on HMS ''Caledon'' during the

Second Battle of Heligoland Bight The Second Battle of Heligoland Bight, also the Action in the Helgoland Bight and the , was an inconclusive naval engagement fought between British and German squadrons on 17 November 1917 during the First World War. Background British minela ...

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 CRH shells for this gun. File:6inchLydditeMkXIIAQNTShellDiagram.jpg,

Surviving examples

* On monitor at

Portsmouth Historic Dockyard Portsmouth Historic Dockyard is an area of HMNB Portsmouth, HM Naval Base Portsmouth which is open to the public; it contains several historic buildings and ships. It is managed by the National Museum of the Royal Navy as an umbrella organizatio ...

, UK
A gun from HMAS ''Adelaide''
at HMAS ''Cerberus'' naval base, Victoria, Australia

Notes and references

Bibliography

* *
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
{{DEFAULTSORT:BL 06-inch Mk 12 gun Naval guns of the United Kingdom World War I naval weapons of the United Kingdom World War II naval weapons of the United Kingdom 152 mm artillery Vickers Coastal artillery