RML 11 inch 25 ton gun

• Name — Ordnance RML 11-inch 25-ton gun • Type — Naval gun Coast defence gun • Is Ranged — YES • Is Artillery — YES • Is Uk — YES • Service — 1867–1903 • Used By — Royal Navy • Wars — Bombardment of Alexandria • Manufacturer — Royal Arsenal • Unit Cost — £1,589 (18751) • Variants — Mk I, Mk II • Weight — 25 long ton • Part Length — 145 in (bore + chamber) • Cartridge — 532 to Palliser, Common, Shrapnel • Caliber — 11 in • Velocity — 1360 ft/s

• Illustration — Mark I & II gun construction Mark I was introduced in 1867. Mark II was introduced in 1871 using the simpler and cheaper "Fraser" gun construction method which had proved successful with the RML 9-inch 12-ton Mk IV gun. In 1874 the process of development made a "New Eighty-one Ton Gun" available in Woolwich.

Guns were mounted on: • HMS Alexandra, commissioned 1877. • HMS Temeraire, commissioned 1877.

When the gun was first introduced projectiles had several rows of "studs" which engaged with the gun's rifling to impart spin. Sometime after 1878, "attached gas-checks" were fitted to the bases of the studded shells, reducing wear on the guns and improving their range and accuracy. Subsequently, "automatic gas-checks" were developed which could rotate shells, allowing the deployment of a new range of studless ammunition. Thus, any particular gun potentially operated with a mix of studded and studless ammunition. The gun's primary projectile was 536-543 lb "Palliser" armour-piercing shot, which were fired with a "Battering charge" of 85 lb of "P" (gunpowder) or 70 lb of "R.L.G." (gunpowder) for maximum velocity and hence penetrating power. Shrapnel and Common (exploding) shells weighed 532-536 lb and were fired with a "Full charge" of 60 lb "P" or 50 lb "R.L.G.".

• Illustration — Mk II gun at Fort Nelson, Portsmouth, UK • Illustration — RML 11-inch 25-ton gun at Fort George in St. George's, Bermuda. • Two Mark II guns, number 12 and 14 at Fort George, Bermuda: • Mark II gun number 30 at Fort Nelson, Portsmouth, UK • Three Mark II guns on Drake's Island, Plymouth, UK • Four guns outside Fort Saint Elmo, Malta • Mark II gun dated 1871 outside Fort St. Catherine, Bermuda