MG 131

MG 131
Maschinengewehr 131
Type	Heavy machine gun
Place of origin	Nazi Germany
Service history
In service	1940–1945
Used by	Germany
Wars	World War II
Production history
Designed	1938
Manufacturer	Rheinmetall-Borsig
Produced	1940–1945
Specifications
Weight	16.6 kg (37 lb)
Length	1,170 mm (46 in)
Barrel length	550 mm (22 in)
Cartridge	13×64mmB
Caliber	13 mm (0.51 in)
Action	Recoil-operated; short recoil, closed bolt
Rate of fire	900 round/min
Muzzle velocity	750 m/s (2,500 ft/s)
Effective firing range	1,800 m (2,000 yd)
Feed system	Belt-fed

The MG 131 (shortened from German: Maschinengewehr 131, or "Machine gun 131") was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945. The MG 131 was designed for use at fixed, flexible or turreted, single or twin mountings in Luftwaffe aircraft during World War II.

It was one of the smallest, if not the smallest among the heavy machine guns, the weight was less than 60% of the M2 Browning or the Breda 12.7 mm. Despite this, the MG 131 was a rapid fire weapon with an elevated firepower for its mass. It was equipped with HE rounds. The nearer equivalent could have been the Ho-103. The other Axis main machine gun, the Breda 12.7 mm, was around 13 kg heavier and bigger, while slower by at least 150 rpm. The small size of the MG 131 meant the possibility to replace the 7.92 mm machine guns even in the small nose of the Luftwaffe fighters, which was commonplace from 1943 onwards. This weapon was a marked improvement as the greater armour protection Allied aircraft received rendered smaller calibers almost useless. This was especially true when it came to heavy Allied bombers.

It was installed in the Messerschmitt Bf 109, Me 410 Hornisse, Fw 190, Ju 88, Junkers Ju 388, He 177 Greif bomber, and many other aircraft. The Fernbedienbare Drehlafette FDL 131Z remotely controlled gun turret system, used as a forward-mount dorsal turret on the He 177A, used two MG 131s for dorsal defense, with the experimental Hecklafette HL 131V manned aircraft tail turret design, meant to be standardized on the never-built A-6 version of the He 177A, was also meant for standardization on many late-war prototype developments of German heavy bomber airframes such as the separately developed four engined He 177B and the 1943–44 Amerika Bomber design contender from Heinkel, the BMW 801E radial-powered Heinkel He 277, both airframes being intended to use the HL 131V tail turret unit mounting four MG 131s, two guns each mounted in each of a pair of rotating exterior elevation carriages on either side of the seated gunner, with horizontal traverse executed by the turret core's rotation. The design of the turret originated with the Borsig division of Rheinmetall-Borsig (the manufacturer of the guns themselves) and was a design with promise, using hydraulic drive to both elevate the turret through a 60º arc of both elevation and depression, with a capability for horizontal traverse of some 100º to either side, all at a top traverse angular speed of 60º per second. The Hecklafette tail turret design was never produced beyond a small number of prototype test examples and engineering mockups from 1943 onwards, with few relics of their existence remaining.