The Maschinengewehr 51 (MG51) General Purpose Machine Gun (GPMG) was developed in Switzerland in the years immediately following the end of World War 2 (1939-1945). The design was highly influenced by the excellent German Army MG42 appearing during the conflict and, therefore, exhibited the same general shape, operation and layout. The MG51 was officially adopted in 1951, hence its formal designation, with production handled by the state-owned Waffenfabrik Bern (usually abbreviated as "W+F"). Beyond its acceptance by Swiss Army forces, the MG 51 was also adopted by Denmark.
The MG51 was born from a World War 2 initiative intending to replace the aged Furrer LMG25 and Waffenfabrik Bern MG11 series of light and heavy machine guns, respectively. The LMG25 was adopted in 1925 and was a "rifle-like" automatic weapon fired from the shoulder while supported under the barrel by a bipod assembly. It was chambered for the 7.5x55mm GP11 cartridge operating under a recoil action and fed from a 30-round detachable box magazine. The MG11, an even older firearm adopted in 1911, was based on the successful water-cooled Maxim machine gun of 1889. This weapon was chambered for the same Swiss cartridge and operated from a short-recoil action while being fed through a canvas-and-metal belt arrangement. Both weapons had seen their best days by the time of World War 2 and an official change to a modernized type was in order.
Despite an open competition approach that included both the SIG and Hispano-Suiza concerns, the state-owned Waffenfabrik Bern's interpretation of the German wartime MG42 eventually won out. Working prototypes were unveiled in 1944 and subsequently set through the requisite evaluation and testing paces. With some modifications to suit the Swiss Army requirement, a finalized form of the weapon emerged in 1950 and formally adopted the following year.
Despite its MG42 origins, the MG51 deviated from its predecessor in that it was constructed of high-end milled steel rather than stamped sheets. Locking flaps were then assigned to the internal bolt assembly as opposed to the rollers as seen in the wartime German model. All of these changes made for a heavier end-product but one that proved just as reliable and robust as the original German offering. The weapon fired from the short recoil principle to a rate of 1,000 rounds per minute at a muzzle velocity of 2,500 feet per second. Ranging was accomplished through available, optional gun optics backed up by traditional iron sights. The MG51 was commonly issued with a heavy-duty tripod assembly that could collapse for ease-of-travel. The pad came complete with carrying straps for "over the back" placement as well as pads to sooth pressure against the carrier's shoulders. Early MG51 production forms were given wooden shoulder stocks and pistol grips though these, with the changing of the times, eventually gave way to plastic types.
The MG51 was initially chambered for the standard-issue 7.5x55mm Swiss (M1911) cartridge originating in 1889 and still undergoing quantitative production today (2013). Feeding of the weapon was through 50-round belts from an awaiting ammunition pack seated beside the weapon (the belt entering through the left side of the receiver). Expanded Swiss military commitments and NATO involvement eventually introduced the 7.62x51mm chambering into the mix. Those MG51 systems procured by Denmark were modified to fire the localized American 30-06 Springfield cartridge.
As the MG51 took the place of both a light and heavy weapon system, the new design was adopted as a fire support and sustained fire solution. For the former, a bipod assembly could be fitted and, in the latter, the aforementioned heavy tripod was utilized. The weapon was further evolved into a vehicle-mounted version under various "Pz Mg" marks to promote improved logistics within the Swiss Army inventory as well as manage a limited defense budget. The MG51 currently sees active service in the Swiss Amy ranks.