QF 12 pounder 18 cwt naval gun

The QF 12 pounder 18 cwt gun was a 3 inch high-velocity naval gun used to equip larger British warships such as battleships for defence against torpedo boats. 18 cwt referred to the weight of gun and breech (18 × 112 lb = 2,016 lb or 914 kg), to differentiate the gun from others that also fired the "12 pound" (actually 12.5 lb or 5.7 kg) shell.

Royal Navy service


Guns were mounted in:
 * HMS Dreadnought commissioned 1906
 * The last three King Edward VII-class battleships—HMS Britannia, HMS Africa, and HMS Hibernia, commissioned 1906–1907
 * Lord Nelson-class battleships commissioned 1908
 * Minotaur-class armoured cruisers commissioned 1908–1909

The gun was superseded in the anti-torpedo boat role on new capital ships from 1909 onwards by the far more powerful BL 4-inch Mk VII gun.

World War I land service
In World War I four guns were landed for service in the East Africa campaign, on 10 February 1916, and were used until September. They constituted the 9th Field Battery manned by Royal Marines. They were originally towed by oxen and later by Napier lorries. 

Ammunition
The gun fired the same 12.5 lb 3 in shells as the other British "QF 12 pounder" guns, but used its own larger separate cartridge case to accommodate a larger quantity of cordite propellant.