A U.S. 57 mm M1 gun firing from Champs-Vauverts gate in Saint-Malo intramuros, in Bretagne in August 1944. It seems to be a reconstructed scene for the movie needs of John Ford who followed Patton's army. The 57mm Gun M1, which was produced in the United States from 1942 to 1945, was the American version of the British 6 Pounder anti-tank gun. Because of production differences between the two countries, there were differences between the M1 and the 6 Pounder. The M1 had a slightly longer barrel than the 6 Pounder. The longer barrel gave the M1 an increased muzzle velocity of 2793ft/s (853m/s). The 57mm M1 anti-tank gun fired two different types of armor piercing round – the AP and the APC – as well as a high explosive round. It was successfully mounted on self propelled carriages, which were used by the British in North Africa. The strong recoil from the M1 made it unpopular with gunners. The M1 anti-tank gun continued to be used after production ceased in 1945. After World War II ended, the US gave M1s to other countries as a form of military aid. The guns remained in service in these countries for decades. Central American republics were using M1s at least until the 1980s.
Source :
https://commons.wikimedia.org/wiki/File:57mm_Gun_M1_-_Saint-Malon_Bretagne.jpg
https://www.tanks.net/anti-tank-weapons/united-states-57mm-gun-m1.html
