RML 8 inch 9 ton gun

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Ordnance RML 8 inch 9 ton gun
Gun Deck HMS Northumberland.jpg
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[1]
Variants Mk I - Mk III
Weight 9 long tons (9.1 t)
Barrel length 118 inches (3.0 m) bore + chamber[2]

Shell 174 pounds 12 ounces (79.3 kg)[3]
Calibre 8-inch (203.2 mm)
Muzzle velocity 1,420 feet per second (430 m/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 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.[6]

See also[edit]

Surviving examples[edit]

Notes and references[edit]

  1. ^ Unit cost of £567 12 shillings 10 pence is quoted in "The British Navy" Volume II, 1882, by Sir Thomas Brassey. Page 38
  2. ^ Text Book of Gunnery 1887 Table XVI page 313
  3. ^ 174 lb 12 oz projectile. Text Book of Gunnery 1887 Table XVI page 313
  4. ^ 1,420 feet/second firing 174-pound 12-oz projectile . Text Book of Gunnery 1887 Table XVI page 313
  5. ^ Mark I - Mark III = Mark 1 through to Mark 3. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. Hence this article describes the three models of RML 8-inch guns.
  6. ^ Gas-checks in British RML heavy guns


External links[edit]