BL 6 inch Mk XXII naval gun

The BL 6-inch Mk XXII gun was a British high-velocity 6-inch 50-calibre wire-wound naval gun originally designed as secondary armament for the canceled G3 class battlecruisers. When the G3 class of battlecruisers were canceled after the Washington Naval Treaty the guns and mountings were later used as secondary armament on the two Nelson-class battleships, serving throughout World War II. The Nelson's were the first British battleships since the Lord Nelson class of 1904 to carry their secondary armament in turrets rather than in broadside casemates. The Mk VIII gun mountings could elevate from +60 degrees to -5 degrees, while the telescopic power rammers for the gun loaded at a +5 degree fixed angle. Although classified as a dual-purpose gun and capable of high-angle fire their training and elevation speeds were too slow for the anti-aircraft role and their main use was against surface targets.