| Maschinengewehr MG 151 | |
|---|---|
 MG 151/20 – normal (fig.1) vs. electric (fig.3) ignition MG 151/15 – normal (fig.2) vs. electric (fig.4) ignition | |
| Type | Aircraft cannon |
| Place of origin | Germany |
| Service history | |
| Used by | See users |
| Wars | See wars |
| Production history | |
| Manufacturer | Waffenfabrik Mauser AG |
| Produced | 1940-1941 – MG 151/15 1941-1945 – MG 151/20 (Nazi Germany) |
| Variants | MG 151/15 (see specs) MG 151/20 (see specs) |
The Maschinengewehr (MG) 151 is a belt-fed autocannon for aircraft use, developed in Nazi Germany from 1934 to 1940 and produced by Waffenfabrik Mauser during World War II. It was originally produced in 15.1 mm caliber from 1940, with a 15×96mm cartridge, but due to demand for higher effect against aircraft, especially with the introduction of mine shells for the 20 mm MG-FF/M aircraft cannon, the design was rechambered to 20 mm caliber in 1941, using a newly developed 20×82mm cartridge which traded projectile velocity for explosive power. The initial 15 mm variant then became known as the MG 151/15, with the new 20 mm variant becoming the MG 151/20.
The MG 151/20 cannon was widely used on German Luftwaffe combat aircraft throughout World War II, mainly as offensive armament, but also seeing some use as defensive guns. Existing MG 151/15 guns saw use as aircraft armament throughout the war, albeit more limited compared to the MG 151/20, but also as anti-aircraft guns in various configurations, such as the SdKfz 251/21 Drilling half-track which carried three MG 151/15.
Post-war, salvaged MG 151/20 saw usage by many nations. France had salvaged many guns and became the main user and exporter of the MG 151/20 during the Cold War, fitting it to not only aircraft, but also armoured fighting vehicles as anti aircraft weaponry. France continued exporting the gun all the way into the 1960s, then primarily as flexible dorsal gunship armament for the Aérospatiale SA-3160 and SA-3164 Alouette III utility helicopter. SA-3160s armed with MG 151/20s were bought by Portugal, Rhodesia and South Africa in 1966 and saw service until the early 1990s. South Africa reused the 20×82mm cartridge from the MG 151/20 to chamber their Denel NTW-20 anti-materiel rifle.