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.

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 Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag inclusions (up to 2% by weight), which give it a wood-like "grain" t ...

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 Cascabel may refer to: * Cascabel (artillery), a subassembly of a muzzle-loading cannon * Cascabel chili, a small, round chili pepper * Cascabel, a Shuttle Loop roller coaster at Chapultepec Park in Mexico City * Spanish common name for ''Crotalu ...

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.

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.

Gas-checks in British RML heavy guns Gas-checks were attachments to ammunition that revolutionised the performance of RML heavy guns. The first generation of RML heavy guns began entering service in about 1865. They all had Woolwich rifling and relied on studs on the projectiles for ...

Surviving examples

Notes and references

Bibliography

Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE
* Sir Thomas Brassey
The British Navy, Volume II. London: Longmans, Green and Co. 1882

External links