|Type||Heavy machine gun|
|Place of origin||Germany|
|Wars||World War II|
|Weight||16.6 kg (37 lb)|
|Length||1.17 m (1.28 yd)|
|Barrel length||1,140 mm (45 in)|
|Caliber||13 mm (0.51 in)|
|Action||Recoil-operated; short recoil|
|Rate of fire||900 round/min|
|Muzzle velocity||750 m/s (2,500 ft/s)|
|Effective firing range||1,800 m (2,000 yd)|
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 also 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, as it happened since 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 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 Hecklafette tail turret design was never produced beyond a small number of prototype and test examples from 1943 onwards, with few relics of their existence remaining.
The MG 131 fired electrically primed ammunition in order to sustain a high rate of fire when shooting through the propeller disc of a single-engined fighter. A pair of MG 131 machine guns was used as cowl armament on later models of the Bf 109G (which originally required one blister or Beule on each side of the fuselage, flanking the upper rear end of the engine, to house the larger breech of the new gun) and the Fw 190.
- Weight : 16.6 kilograms (37 lb)
- Length : 1.17 metres (3.8 ft)
- Muzzle velocity : ~ 750 metres per second (2,500 ft/s)
- Rate of fire : ~ 900 rounds per minute
- 13 mm APT 710 m/s, projectile mass 38.5 grams (594 gr), muzzle energy 9,700 joules (7,200 ft·lbf)
- 13 mm API 710 m/s, projectile mass 38 grams (590 gr), muzzle energy 9,580 joules (7,070 ft·lbf)
- 13 mm HEI-t with 1.4 grams (22 gr) PETN + 0.3 grams (4.6 gr) thermite 750 metres per second (2,500 ft/s), projectile mass 34 grams (520 gr), muzzle energy 9,560 joules (7,050 ft·lbf)