| Is Artillery: | yes |
| Is Explosive: | yes |
| Is Uk: | yes |
| Is Ranged: | yes |
| BL 6-inch Mk XII naval gun | |
| Origin: | United Kingdom |
| Used By: | British Empire |
| Wars: | |
| Type: | Naval gun |
| Designer: | Vickers |
| Design Date: | 1913 |
| Manufacturer: | Vickers |
| Service: | 1914–2011 |
| Caliber: | 6inches |
| Part Length: | 270inches bore (45 cal)[1] |
| Breech: | Welin interrupted screw |
| Rate: | 5-7 rpm |
| Velocity: | 2825ft/s[2] |
| Cartridge: | 100lb Lyddite, Armour-piercing, Shrapnel[3] |
| Elevation: | −7°–30°[4] |
| Max Range: | 19660m (64,500feet)[5] |
| Recoil: | Hydro-spring, 16.5inch[6] |
| Weight: | 15512lb barrel & breech[7] |
| Number: | 463 |
The BL 6-inch Mark XII naval gun[8] 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.
It superseded the 45-calibre Mk VII gun and the longer 50-calibre Mk XI gun which had proved unwieldy in light cruisers due to its length, and was Britain's most modern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It was superseded as secondary armament on new battleships in the 1920s by the 50-calibre 6-inch Mk XXII gun, and as main armament on new light cruisers in the 1930s by the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.[10]
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.