AC 47 anti-tank gun

The AC 47 was a French anti-tank gun of 47mm caliber. It was principally used in the "ouvrages" and casemates of the Maginot Line in the late 1930s; another version was created for naval use.
The AC 47 was principally used as a defensive weapon, since its portability was intentionally limited to prevent the weapon from being turned on defending troops if a fortification was captured.