RML 9-inch 12-ton gun

Ordnance RML 9-inch 12-ton gun
Restored Mark I, RML 9-inch 12-ton gun being fired at Simon's Town in 2014, with replica ammunition in the foreground
TypeNaval gun
Coast defence gun
Place of originUnited Kingdom
Service history
In service1865–1922 (Mk VI)
Used byRoyal Navy
Australian Colonies
Spanish Navy
WarsBombardment of Alexandria
Production history
Designed1865
ManufacturerRoyal Arsenal
Unit cost£1000 in 1875, £740 in 1882 (£94,000 in 2025)
VariantsMk I–VI
Specifications
Mass12
Length156 inches (4.0 m)
Barrel length125 inches (3.2 m) (bore)

ShellMk I–V : 250 to 256 pounds (113.4 to 116.1 kg) Palliser, Common, Shrapnel
Mk VI : 360 pounds (163.3 kg) AP
Calibre9-inch (228.6 mm)
BreechNone, loaded through muzzle
Muzzle velocity1,420 feet per second (430 m/s)
Maximum firing range9,919 yards (9,070 m)

The RML 9-inch guns Mark I – Mark VI were large rifled muzzle-loading guns of the 1860s used as primary armament on smaller British ironclad battleships and secondary armament on larger battleships, and also ashore for coast defence. It should not be confused with the RML 9-inch Armstrong Gun, used by the Dutch navy, the Spanish Navy, and other navies.