QF 4.5-inch Mk I – V naval gun
| Ordnance QF 4.5 inch gun Mk I, II, III, IV, V | |
|---|---|
Mk III guns in BD 'RP10' Mk II mountings on Implacable-class aircraft carrier. A King George V-class battleship (1939) can be seen in the background. | |
| Type | Naval gun Anti-aircraft gun |
| Place of origin | United Kingdom |
| Service history | |
| Used by | British Commonwealth |
| Wars | Second World War Korean War Falklands War |
| Production history | |
| No. built | Navy: c. 800 Army: 474 |
| Specifications | |
| Barrel length | Bore: 16 ft 8 in (5.08 m) 45 calibres |
| Shell | Fixed or Separate QF 113 640–645 mm R |
| Shell weight | 55 pounds (24.9 kg)× |
| Calibre | 4.45-inch (113 mm) |
| Breech | Mks I - IV: Horizontal sliding block Mk V: Vertical sliding block |
| Elevation | 0° to +80° |
| Traverse | 360° |
| Rate of fire | 12 RPM for Mk II BD mount. 16 RPM recorded for Mk III UD mount. |
| Muzzle velocity | 2,449 ft/s (746 m/s) |
| Maximum firing range | 20,750 yd (18,970 m) at 2,449 ft/s (746 m/s) AA:41,000 ft (12,500 m) |
The QF 4.5 inch gun has been the standard medium-calibre naval gun used by the Royal Navy as a medium-range weapon capable of use against surface, aircraft and shore targets since 1938. This article covers the early 45-calibre family of guns up to the 1970s. For the later unrelated 55-calibre Royal Navy gun, see 4.5 inch Mark 8 naval gun. Like all British nominally 4.5 inch naval guns, the QF Mk I has an actual calibre of 4.45 inches (113 mm).