12-pounder gun or 12-pdr, usually denotes a gun which fired a projectile of approximately 12 pounds.
Guns of this type include:
A cannon sized for a 12-pound ball, see Naval artillery in the Age of Sail
Canon de 12 de Vallière French cannon of 1732
Canon lourd de 12 Gribeauval French heavy cannon of the mid-late 18th century
Canon de 12 Gribeauval French field cannon of the mid-late 18th century
12-pounder long gun, the naval muzzle-loader of the Age of Sail
Canon obusier de 12 French 12 cm field gun of 1853. Known in the US as "12 pounder Napoleon"
RBL 12 pounder 8 cwt Armstrong field gun of 1859
one of the Dahlgren guns of the American Civil War
Ordnance BL 12 pounder 7 cwt Field gun, 1885–1892
Ordnance QF 12 pounder 8 cwt Naval landing gun, late 19th century & early 20th century
Ordnance BL 12 pounder 6 cwt Light field gun, 1894–1916
QF 12 pounder 12 cwt naval gun "Long 12" 1890s - 1940s
QF 12 pounder 12 cwt AA gun World War I
QF 12 pounder 18 cwt naval gun 1904 - 1920s
Erroneously, the QF 3 inch 20 cwt gun
