QF 5.25-inch naval gun

QF 5.25-inch Mark I
5.25-inch turret on HMS Sirius. The empty cartridge cases from firing in support of the Allied invasion of Normandy, June 1944
TypeDual-purpose gun
Place of originUnited Kingdom
Service history
In service1940-1985 (naval)
1942-1960s (land)
Used byRoyal Navy
Royal Artillery
Royal Australian Artillery
WarsWorld War II
Korean War
Production history
Designed1935
VariantsMk I, Mk II
Specifications
MassBarrel & breech: 9,616 lb (4,362 kg)
LengthTotal: 22 ft 11.5 in (7 m)
Barrel lengthBore: 21 ft 10.5 in (6.67 m) 50 calibres

Shell133x782 mm R
Separate QF, 80 pounds (36.29 kg)
Calibre5.25-inch (133 mm)
Elevation-5 to +70 degrees
Rate of fire7-8 rpm sustained fire
Muzzle velocityNaval: 2,672 ft/s (814 m/s)
Army AA: 2,800 ft/s (850 m/s)
Effective firing rangeNaval: 23,400 yd (21,400 m) at 45 degrees with HE shell at 2,600 ft/s (790 m/s)
AA: 36,000 ft (11,000 m)
Maximum firing rangeNaval: 24,070 yd (22,010 m) at 45 degrees with HE shell at 2,672 ft/s (814 m/s)
AA: 46,500 ft (14,200 m)

The QF 5.25-inch Mark I gun was the heaviest dual-purpose gun used by the Royal Navy during the Second World War. Although considered less than completely successful, it saw extensive service. 267 guns were built.