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RML 8 inch gun

Ordnance RML 8 inch 9 ton gun
Gun Deck HMS Northumberland.jpg
Gundeck of HMS Northumberland
Type Naval gun
Coast defence gun
Place of origin United Kingdom
Service history
In service 1866 - 190?
Used by Royal Navy
Production history
Manufacturer Royal Arsenal
Unit cost £568
Variants Mk I - Mk III
Specifications
Weight 9 long tons (9.1 t)
Barrel length 118 inches (3.0 m) bore + chamber

Shell 174 pounds 12 ounces (79.3 kg)
Calibre 8-inch (203.2 mm)
Muzzle velocity 1,420 feet per second (430 m/s)

The British RML 8 inch 9 ton guns Mark I - Mark III 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 320 inches) 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.


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