37mm Anti-Tank Gun M3

The USA's 37mm Light Anti Tank Gun M3 was derived from the 3.7cm PaK 36/36 produced by Germany's Rheinmetall-Borsig. The USA made a number of changes to the German design and considering the German weapon became obsolete quite quickly following the outbreal of WWII this was a good idea.
The M3 was lighter and was improved with a five baffle muzzle brake to help control the recoil forces.
After 1941 the 37mm M3 was next to useless in the European theatre so most of the 18,702 produced were employed in the Pacific Theatre where they were used for Infantry support firing HE and Cannister rounds.