| RBL 40-pounder gun | |
|---|---|
 Diagram from 'Treatise on Service Ordnance' (HMSO), 1877 | |
| Type | Naval gun Fortification gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1860s – 1900? |
| Used by | United Kingdom Australian colonies |
| Wars | New Zealand Wars Bombardment of Kagoshima |
| Production history | |
| Designer | W.G. Armstrong Co. |
| Manufacturer | W.G. Armstrong Co. Royal Gun Factory |
| Produced | 1859 – 1863 |
| No. built | 1013[1] |
| Variants | 32cwt, 35cwt |
| Specifications | |
| Mass | 32 cwt (3,584 pounds (1,626 kg)), later 35 cwt (3,920 pounds (1,780 kg)) gun & breech[2] |
| Barrel length | 106.3 inches (2.700 m) bore & chamber[2] |
| Shell | 40 pounds 2 ounces (18.20 kg)[2] |
| Calibre | 4.75-inch (120.6 mm)[2] |
| Breech | Armstrong screw with vertical sliding vent-piece (block) |
| Muzzle velocity | 1,180 feet per second (360 m/s)[3] |
The Armstrong RBL 40-pounder gun was introduced into use in 1860 for service on both land and sea. It used William Armstrong's new and innovative rifled breechloading mechanism. It remained in use until 1902 when replaced by more modern Breech Loading (BL) guns.
- ^ 1013 were in service in 1877 : 819 35cwt & 194 32cwt. Quoted in Treatise on Manufacture of Ordnance 1877, page 150. Holley 1865, page 13 quotes 641 as at 1863 : 535 manufactured by Elswick Ordnance and 106 by the Royal Gun Factory. From the Report of the Select Committee on Ordnance, 1863.
- ^ a b c d Text Book of Gunnery, 1887
- ^ 1180 ft/sec firing 40 lb 2 oz projectile with 5 lb RLG2 (gunpowder). Text Book of Gunnery 1887, Table XVI page 313