QF 4-inch naval gun Mk IV, XII, XXII
| Ordnance QF 4 inch gun Mk IV, XII, XXII | |
|---|---|
| Type | Light Naval gun Submarine gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1911-1940s |
| Used by | United Kingdom |
| Wars | World War I World War II |
| Production history | |
| No. built | 1,141 |
| Specifications | |
| Mass | 2,750 pounds (1,250 kg) barrel & breech |
| Barrel length | 160 inches (4.064 m) bore (40 calibres) |
| Shell | Mk IV : Separate QF 31 pounds (14.06 kg); Mk XII & XXII : Fixed QF 31 pounds (14.06 kg), 35 pounds (15.88 kg) from 1944 |
| Calibre | 4-inch (101.6 mm) |
| Breech | horizontal sliding-block |
| Elevation | PIX Mount -10° to +20° CPIII Mount -10° to +30° |
| Muzzle velocity | Mk IV : 2,370 feet per second (720 m/s) Mk XII & XXII : 1,873 feet per second (571 m/s) |
| Maximum firing range | 11,580 yards (10,590 m) at +30° |
The QF 4-inch gun Mk IV was the main gun on most Royal Navy and British Empire destroyers in World War I. It was introduced in 1911 as a faster-loading light gun successor to the BL 4 inch Mk VIII gun. Of the 1,141 produced, 939 were still available in 1939. Mk XII and Mk XXII variants armed many British interwar and World War II submarines.