The MG 131 (short for Maschinengewehr 131, meaning "Machine Gun 131") is a Nazi German 13mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and was produced between 1940 and 1945. This large caliber machine gun was the basic system consisting on arms of German aircraft, and largely replaced the weaker MG 17 on many aircraft like the Bf 109G series. The machine gun was widely used as synchronous, turret and wing armaments.
Compared to other heavy machine guns used by other nations (namely the M2 Browning and the Breda-SAFAT 12.7mm), it was one of the smallest, if not the smallest among the heavy machine guns, weighing in at roughly 60% less than either the SAFAT or the Browning. Despite this, the MG 131 was still capable of doing roughly the same damage at an elevated rate of fire.