The QF 12 pounder 12 cwt gun was a common, versatile 3-inch (76 mm) calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, and exported to allied countries. In British service, "12 pounder" was a rounded reference to the projectile weight and "12 cwt" referred to the weight of the barrel and breech : 12 hundredweight = 12 x 112 pounds = 1344 pounds, to differentiate it from other "12 pounder" guns.