BL 4-inch Mk VII naval gun
| Ordnance BL 4-inch gun Mk VII | |
|---|---|
On HMAS Australia, 1918 | |
| Type | Naval gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1908–1945 |
| Used by | United Kingdom |
| Wars | World War I World War II |
| Production history | |
| No. built | 600 |
| Specifications | |
| Mass | 4,704 pounds (2,130 kg) (barrel & breech) |
| Barrel length | 201.25 inches (5.112 m) bore (50.3 calibres) |
| Shell | 31 pounds (14.06 kg) Common pointed, Common lyddite |
| Calibre | 4 inches (101.6 mm) |
| Breech | Welin, Single-motion screw |
| Elevation | -10 degrees to +15 degrees |
| Rate of fire | 6-8 rpm |
| Muzzle velocity | 2,852 feet per second (869 m/s) |
| Maximum firing range | 11,600 yards (10,600 m) at 15° |
The BL 4-inch gun Mk VII was a British high-velocity naval gun introduced in 1908 as an anti-torpedo boat gun in large ships, and in the main armament of smaller ships. Of the 600 produced, 482 were still available in 1939 for use as coastal artillery and as a defensive weapon on Defensively Equipped Merchant Ships (DEMS) during the Second World War.