The 37mm M3 is the first anti-tank gun made in the United States. But at that time, the United States had no experience in manufacturing such weapons. In January 1937, the United States obtained two samples of German 3.7 cm PaK 35/36 anti-tank for reference. The following year during 1938 several different artillery and gun mounts were designed for testing and the T10 artillery body and T5 gun mount were rated as the better choices. Later, these initial models were modified and named M3 37 mm anti-tank guns, and mass production in the early 1940s came from the front door guns. It was a standardized anti-tank gun for the US Infantry Division and Marine Corps at the time. It is usually towed by a 4 x 4 1/4 ton jeep or a larger 3/4 ton Dodge truck. The 37mm M3A1, which entered service in March 1942, was partially modified including the muzzle brake. More than 10,000 such artillery pieces were produced. This weapon was shipped to Europe in the middle of 1943 until it was replaced by the 57 mm M1 of the British 6-pound gun. But in the Pacific M3A1 was used until the end of the war. The M3A1 can fire M51 armor-piercing ammunition and can penetrate a 60-mm vertical armor plate at a distance of 1,000 meters.