The M1 is an almost exact copy of the British six-pounder anti-tank gun. The British design was first modified to American manufacturing practices and standards in order to produce the weapon for Great Britain under Lend-Lease. Production of the U.S. M1 anti-tank gun began in May 1941, and approximately 16,000 were made through 1945. The gun was light, easy to maneuver on the battlefield, and fired both armor-piercing ammunition and a high-explosive shell. Compared to American designed artillery, it had a horrendous recoil that was not popular with troops. The weapon was retired at the end of World War II.The World War II Tank DestroyerBuilt with the intention of destroying German tanks, the "Quick Firing" six pounder (QF-6) was a British anti-tank gun. Designed in 1940, the weapon system was designed to be a lightweight, armor-piercing system capable of being deployed in a large number of roles. Due to production issues, it did not enter service until the beginning of the North African Campaign in 1942. The American-produced M1 began production in early 1942, with the more heavily modified and upgraded version (the M1A2) entering production later that year.By 1943, the U.S. began to favor the M1A2 over the smaller 37MM M3 gun. Despite initial reluctance to include the weapon in Army inventory, the M1 became standard issue by May 1944. During the invasion of Normandy that June, the U.S. was equipped with Mark II and III revisions of the British QF-6, with the majority of M1s positioned elsewhere on the western front.The M1 itself was capable of firing an assortment of shells and artillery rounds. Many of these shells were armor piercing, allowing the M1 to effectively fulfill its role as an anti-tank weapon. However, it also fired smaller high-explosive and incendiary shells, which made it a viable field artillery component. The M1 variant saw a great number of exported operators due to the Lend-Lease program, with many units being sent to France and the Soviet Union.The QF-6 and M1 remained in limited operation up through the 1970s, when it saw its last use during the 1971 war between India and Pakistan.