3 pounder gun

3 pounder gun, 3 pounder, 3-pdr or QF 3-pdr is an abbreviation typically referring to a gun which fired a projectile weighing approximately 3 pounds. It may refer to :
 * The Grasshopper cannon : of the 18th century
 * QF 3 pounder Hotchkiss : Hotchkiss 47mm naval gun used by many countries from 1885
 * Ordnance QF 3 pounder Vickers : British Vickers 47mm naval gun of World War I and World War II
 * OQF 3 pounder gun : used to arm interwar Vickers Medium Tanks