The M3 was the standard anti-tank gun used the U.S. Army at the beginning of World War II. When it was first used in combat in North Africa in late 1942, soldiers learned that it was too light of a caliber for use against German tanks. By the end of 1943, it was only used for training.The First American Tank DestroyerThe M3 anti-tank gun was the first dedicated anti-tank gun produced by the United States in any meaningful quantity. It was the standard anti-tank gun and had a size and weight that allowed it to be deployed into any environment. The entire assembly weighed just over 900 pounds, allowing it to be towed by jeep or deployed with airborne troops. However, its small size was also one of its greatest weaknesses.During deployment against German armored divisions in North Africa, it was discovered that the gun was ineffective against Panzer and Tiger tanks. Because of this, the gun was quickly replaced with the heavier British QF-6, later modified to American specifications and standards as the M1.During production of the M3, Rock Island Arsenal was responsible for producing the M4 carriage. Production of the entire assembly was carried out between 1940 and 1943, with over 18,000 units produced. Many of these guns were exported under Lend-Lease to China, with a smaller quantity being send to Canada, France, Great Britain and the Soviet Union.Upon the replacement of the M3 with the 57MM M1, many M3s were shipped to the Pacific Theater, where they were used as general artillery for areas not saturated with Japanese mechanized forces. The U.S. continued to use the M3 through the end of the war in the Pacific.The last nations to use the M3 did so until the early 1970s, when the gun was made obsolete by evolving military armor and artillery.