RML 8-inch 9-ton gun

RML 8-inch 9-ton gun
RML 8-inch 9-ton gun
	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
Mass	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^[5] were medium rifled muzzle-loading guns used to arm smaller ironclad warships and coast defence batteries in the later 19th century.

Design

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 in (810 cm)) at the muzzle.

Ammunition

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]

Surviving examples

Notes and references

^ Unit cost of £567 12 shillings 10 pence is quoted in "The British Navy" Volume II, 1882, by Sir Thomas Brassey. Page 38
^ Text Book of Gunnery 1887 Table XVI page 313
^ 174 lb 12 oz projectile. Text Book of Gunnery 1887 Table XVI page 313
^ 1,420 feet/second firing 174-pound 12-oz projectile . Text Book of Gunnery 1887 Table XVI page 313
^ 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.
^ Gas-checks in British RML heavy guns

Bibliography

External links

[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

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