BL 6-inch Mk II–VI naval gun
| Ordnance BL 6-inch gun Mks II, III, IV, VI | |
|---|---|
Mk IV gun on disappearing carriage at Lei Yue Mun Fort, Hong Kong | |
| Type | Naval gun Coast defence gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1880 – 1905 |
| Used by | Royal Navy |
| Production history | |
| Designer | Royal Gun Factory (RGF) |
| Manufacturer | RGF and EOC |
| Variants | Mks II, III, IV, VI |
| Specifications | |
| Mass | Mk II : 81 cwt or 89 cwt (4½ tons) Mks III, IV, VI : 5 tons barrel & breech |
| Barrel length | Mk III : 153.2 inches (3,891 mm) (25.53 calibres) Mk IV, VI : 156 inches (3,962 mm) (26 calibres) |
| Shell | 100 pounds (45.36 kg) |
| Calibre | 6-inch (152.4 mm) |
| Breech | 3 motion interrupted screw. De Bange obturation. |
| Muzzle velocity | Mk III, IV, VI : 1,960 feet per second (597 m/s) QFC guns : 1,913 feet per second (583 m/s) BLC guns : 2,166 feet per second (660 m/s) |
| Maximum firing range | 10,000 yards (9,100 m) |
The BL 6-inch gun Marks II, III, IV and VI were the second and subsequent generations of British 6-inch rifled breechloading naval guns, designed by the Royal Gun Factory in the 1880s following the first 6-inch breechloader, the relatively unsuccessful BL 6-inch 80-pounder gun designed by Elswick Ordnance. They were originally designed to use the old gunpowder propellants but from the mid-1890s onwards were adapted to use the new cordite propellant. They were superseded on new warships by the QF 6-inch gun from 1891.