M-1 57mm Anti Tank Gun on M-2 Carriage
The M1 was essentially the British 6 Pounder anti tank gun introduced into US service in spring 1943. By 1944 the M1 was the standard anti tank gun for US infantry on the Western front although availability of different ammunition types, such as HE, limited its use. US units were sometimes able to get HE ammunition from the British Army.
Captured guns were redesignated 5.7cm Pak 209(e) and 5.7cm Pak 202(a) by the Germans.