BL 6-inch Mk XXII naval gun

The BL 6-inch Mk XXII gun[note 1] was a British high-velocity 6-inch 50-calibre wire-wound naval guns deployed on the Nelson-class battleships from the 1920s to 1945.

Ordnance BL 6-inch gun Mk XXII
Gun turrets on HMS Rodney, 1940
TypeNaval gun
Place of originUnited Kingdom
Service history
In service1927 – 1947
Used byUnited Kingdom
WarsWorld War II
Production history
No. built40
VariantsMark XXII*
Mass19,824 lbs. (8,992 kg)
Barrel length300 inches (7.620 m) bore (50 calibres)

Shell1927 : 100 pounds (45 kg)
1942 : 112 pounds (51 kg)[1]
Calibre6-inch (152.4 mm)
Breech364 lbs. (165.1 kg) Welin interrupted screw
Recoil16.5 in (42 cm)
Elevation-5 / +60 degrees
Traverse+100 / -100 degrees
Rate of fire5 rpm
Muzzle velocity898 metres per second (2,950 ft/s)[1]


They were originally designed as secondary armament for the proposed G3 class battlecruisers. When the G3 class were cancelled 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 Nelsons 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.[2] 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.


The gun originally fired a 100-pound (45 kg) shell, which had been the standard shell weight for six-inch guns since 1880. From 1942 the gun fired the same 112-pound (51 kg) shell introduced for the later Mk XXIII gun.[3] Figures in the table below are for the 100lb shell.

Shell trajectory

Range[2] Elevation Time of flight Descent Impact velocity
5000 yd (4.6 km)  5.2′ 6.20 sec  48′ 2029 ft/s (618 m/s)
10000 yd (9.1 km)  37.2′ 15.22 sec  13′ 1390 ft/s (424 m/s)
15000 yd (14 km) 12° 5.4′ 28.55 sec 23° 2′ 1094 ft/s (333 m/s)
20000 yd (18 km) 22° 54′ 46.14 sec 39° 46′ 1056 ft/s (322 m/s)
25000 yd (22.86 km) 42° 37′ 74.92 sec 59° 0′ 1148 ft/s (350 m/s)

See also

Weapons of comparable role, performance and era


  1. MK XXII = Mark 22. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. This was the twenty-second model of British BL 6-inch gun


  2. Campbell, Naval Weapons of WWII, p.37.
  3. DiGiulian


  • Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.
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