US Marine Corps M3A1 37mm Anti-Tank GunThe 37 mm Gun M3 was the first dedicated anti tank gun fielded by United States forces. Introduced in 1940, it became their standard with its size enabling it to be pulled by a jeep. However, the continuing improvement of German tanks quickly rendered the 37 mm ineffective, and by 1943 it was being gradually replaced in the European and Mediterranean theatres by the more powerful British developed 57 mm Gun M1. In the Pacific, where the Japanese tank