When war was declared in September 1939, the British Admiralty considered how best to use the Queen Mary for the war effort and, after debate that included the strong possibility of conversion to an aircraft carrier, decided that because of her size and speed she was best suited as a troop carrier. For defense, the ship was fitted with a wide array of armament that included five 40 MM machine guns like this twin anti-aircraft heavy machine gun. The barrels measured 94.8 inches, the gun had a range of 3,000 to 5,000 yards, and a crew of seven headed by a gun captain was assigned to man it. The crew kept the guns in good working order and ready for action, frequently firing them for practice. Despite the readiness of the Queen Mary's gun crews, she never encountered enemy action by air or sea and never had cause to fire her guns in anger. Most armament was removed from the ship in May and June 1945, and the remainder was taken off during her post-war refit in 1947.
