| RML 8-inch 9-ton gun | |
| Origin: | United Kingdom |
| Type: | Naval gun Coast defence gun |
| Is Ranged: | YES |
| Is Artillery: | YES |
| Is Uk: | YES |
| Service: | 1866–190? |
| Used By: | Royal Navy |
| Manufacturer: | Royal Arsenal |
| Unit Cost: | £568[1] |
| Variants: | Mk I – Mk III |
| Part Length: | 118inches bore + chamber[2] |
| Cartridge: | 174oz12oz[3] |
| Caliber: | 8sing=onNaNsing=on |
| Velocity: | 1420ft/s[4] |
The British RML 8-inch 9-ton guns Mark I – Mark III[5] were medium rifled muzzle-loading guns used to arm smaller ironclad warships and coast defence batteries in the later 19th century.
In common with other Royal Ordnance RML designs of the 1860s, Mark I used the strong but expensive Armstrong system of a steel tube surrounded by a complex system of multiple wrought-iron coils, which was progressively simplified in Marks II and III to reduce costs : Mark III consisted only of A tube, B tube, breech coil and cascabel screw.
Rifling was of the "Woolwich" pattern of a small number of broad shallow grooves: 4 grooves with twist increasing from 0 to 1 turn in 40 calibres (i.e. in 320inches) at the muzzle.
The ammunition was mainly studded, with the studs engaging in the Woolwich rifling grooves. However, a studless pointed common shell with automatic gas-check also became available later in the gun's life.[6]