The 75 mm gun, models M2 to M6, was the standard American medium caliber gun fitted to mobile platforms during World War II. They were primarily mounted on tanks, such as the M3 Lee and M4 Sherman, but also the B-25 Mitchell medium bomber aircraft, etc. There were five main variants used during the war: M2, M3, M4, M5 and M6. They were considered the standard American tank guns. The M2 and M3 were used on the M3 medium tank, the M3 was used on the M4 Sherman tank, and the M6 was used on the M24 Chaffee light tank. The M3 was also used on Medium Tank M7. The M4 variant was fitted on some North American B-25 Mitchell medium bomber aircraft. History The 75 mm tank gun has its origins in the French Canon de 75 modèle 1897 field gun of World War I , which was also adopted by the United States and used well into World War II as the 75 mm M1897 field gun. The tank and field guns fired the same range of 75x350R ammunition. The primary round was the 6.76 kg (14.9 lb) M48 high explosive round, which travelled at 625 m/s (2,050 ft/s) and contained 1.5 pounds (680 g) of TNT filling (2845 kilojoules of explosive energy) and a choice of two fuzes, the super quick (SQ) and the delay (PD), which had delays of 0.05 and 0.15 seconds respectively. SQ was the standard setting, with PD used against structures, gun positions or lightly protected vehicles. The field gun origins of the ordnance and ammunition ensured that the M2/3/6 series HE round was highly effective for its caliber. The M48 was available in two versions, standard and supercharge, which had an increased propellent charge for greater muzzle velocity ( vs. ) and range (2,300 yards greater). Other rounds fired by the 75 mm tank guns included the T30 canister shot for use against troops in the open at short range. This, which was essentially a giant shotgun shell full of large numbers of steel balls, was used primarily in the Pacific. There was also the M89 base-ejecting hexachloroethane (HC) smoke round and the M64 white phosphorus (WP or "Willy Pete") round, which proved highly effective in the bocage fighting around Normandy. Finally, there were two different armor-piercing rounds. The first armor-piercing round was the M72 AP-T, a plain uncapped armor-piercing round whose