The Maschinengewehr 1942, or MG42, is a German machine gun, first manufactured in 1942 as the successor to the MG34. During WWII, the MG42 had the fastest rate of fire of any weapon, at 1500 rounds per minute (up to 1800). At this rate it becomes impossible for the human ear to discern the sound of individual bullets being fired, and thus when in use the gun makes a sound described both as "ripping cloth" and "Hitler's Buzzsaw". During the war, over 400,000 were manufactured.
In the late 1930s the MG34 was arguably the best machine gun in the world at the time, but was expensive and time consuming to construct. In order to arm the increasingly large German army, an effort was started to build a simpler gun that could be built much faster. The winning design was offered by a newcommer to the contest, Metall-und-Lackierwarenfabrik Johannes Grossfuss AG, experts in pressed and punched steel parts. Their efforts resulted in a dramatic reduction in complexity – it took 75 man-hours to complete the new gun as opposed to 150 for the MG34, and cost 250RM as opposed to 327RM.
The resulting MG39 remained largely similar to the earlier MG34, a deliberate decision made in order to maintain familiarity. The only major change from the gunner's perspective was dropping the drum-feed options, leaving it with belts only, and the further increase in the rate of fire. Although made of "cheap" parts, the prototypes also proved to be considerably more rugged and resistant to jamming than the somewhat tempermental MG34
Given the success of the prototype, it's somewhat mysterious that the gun did not enter production until 1942, thereby requiring a renaming to MG42. As soon as it was introduced it garnered intense demand by field units, a demand that German industry was never able to meet.
The MG42 weighed 11.6kg in the light machine gun role with the bipod, lighter than the MG34 and easily portable. The bipod, the same one used on the MG34, could be mounted to the front or the center of the gun depending on where it was being used. In the role as a heavy machine gun it utilised a newly developed Lafette 42 tripod that weighed 20.5kg on its own. The barrel was lighter than the MG34s and wore out more quickly, but could be replaced in seconds by an experienced gunner.
In 1944 the acute material shortages of the Third Reich led to a newer version, the MG45 (or MG42V), which used steel of lesser quality, reduced weight to only 9kg, and yet further improved the maximum rate of fire. First tests were undertaken in June 1944, but development dragged on and eventually only ten were ever built.
Even today it is still regarded by many experts as the best machine gun ever. The MG42, with minor modifications, is still the primary heavy machine gun of the modern German army, now called the MG3. A number of other armies around the world have adopted versions of the original, and guns looking similar, or identical, to the MG42 remain in widespread service today. The US Army's M-60 is based upon the FG42 paratrooper rifle (Fallschirmjaegergewehr) and MG42.