BL 6-inch Mk XII naval gun


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

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

It superseded the 45-calibres Mk VII gun and the longer 50-calibres Mk XI gun which had proved unwieldy in light cruisers due to its length, and was Britain's most modern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.
It was superseded as secondary armament on new battleships in the 1920s by the 50-calibre 6-inch Mk XXII gun, and as main armament on new light cruisers in the 1930s by the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 :
During WWII some Mk XII guns were used in emergency coast defense batteries.

Notable actions

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.

Weapons of comparable role, performance and era