Nazi Germany took a different path and came up with the Einheitsmaschinengewehr, the “universal machine gun.” Their excellent MG 34, and its successor (and, really, contemporary) MG 42 were the first examples of the modern concept of the General Purpose Machine Gun, and were rightfully feared by the Allies.
 
Germany had been trying to create a machine gun that served well across all roles since the late years of World War I, but the economic ruin caused by the war, and the Treaty of Versailles’ ban on German machine gun manufacturing, halted such development for a while. The German defense ministry picked up the thread and ordered several companies to develop a new universal machine gun in 1932. The Weimar Republic had already been cautiously trying to skirt the Versailles limitations, but rearmament could begin in earnest after Hitler rose to power in 1933 (Becoming Führer).

The machine gun was expected to be light enough to be carried around by infantry, and simple to operate; it had to have a quick-change barrel (the barrel can get very hot during sustained fire and cause a “cook-off,” uncontrolled firing), and had to have both single and fully automatic fire. The winning design was based on an earlier gun, the MG 30, produced by Rheinmetall, and which was adapted and modified by Heinrich Vollmer of Mauser Industries. The end result, the MG 34 (“MG” standing for “Maschinengewehr,” literally “machine gun”), incorporated ideas from many other designs. This led to a bureaucratic tangle as 18 patents filed by three companies were used by the gun, and all patent holders had to receive a part of whatever profit was going to manifest.
 
The MG 34
The MG 34 used the common 7.92×57mm Mauser cartridge, which had been in German use since 1903 in many guns, including the Karabiner 98k, Germany standard issue rifle in World War II. The most common version of the gun had a rate of fire of 800-900 rounds per minute. This was a rather high rate compared to most Allied machine guns. The famous .30 caliber Browning (The .30 cal Browning), for example, had a firing rate of 400-600 rounds per minute and used the .30-06 Springfield cartridge which had slightly more energy than the 7.92 Mauser, but was generally very similar in performance.

The gun could be equipped with a variety of sights for versatility. Beyond the standard iron sight, it could mount a spiderweb sight for anti-aircraft use, various telescopic sights, and even an active infrared one for nighttime use.
 
An overheated barrel could be swapped for a new one in 10-15 seconds. Once a latch was disengaged, the entire receiver would pivot and rotate away, allowing an operator wearing asbestos mitts to reach into the barrel sleeve and pull out the barrel backwards, without having to sit up and expose himself to enemy fire. This operation only required a very small space, making barrel change easy inside cramped armored vehicles armed with MG 34.

The Lafette tripod also came with a Tiefenfeuerautomat, or “depth fire automation.” If the operator was not sure of the exact distance of a target, he could set a range span (e.g. between 2,200 and 2,500 yards), and engage the device. The gun would then automatically elevate and depress while firing to hose that entire span up and down, increasing the chance that some of the rounds will hit.
 
Other specialist mounts include ones for anti-aircraft use, or use on bicycles, motorcycle sidecars, armored vehicles, fortress positions, boat decks and even assault gliders. MG 34s were also mounted in multiple-gun arrangements, especially on vehicles, in an anti-aircraft role.

Several later versions of the MG 34 were developed. The MG 34/41 had an increased rate of fire of 1,200 rounds per minute and greater dispersion so it could suppress a larger area, at the cost of much more stress on the materials. The MG 34 Panzerlauf was the definitive version for use on all armored vehicles except the Jagdpanzer IV tank destroyer. The MG 81 and its twin gun MG 81Z variety were developed for use on aircraft, but were never produced in large enough numbers to replace earlier and less effective designs.
 
The MG 34 was a powerful and versatile weapon, but it wasn’t perfect. While reliable when properly maintained, it was still sensitive to mud, sand and extreme weather. It was also expensive and complicated to produce, and required high-quality alloys with trace minerals the Third Reich didn’t have easy access to during the war. Some of these problems actually arose from a reaction to World War I lessons. Some poison gases were corrosive and could damage guns with loose manufacturing tolerances. Some later guns, the MG 34 included, were built with extremely tight tolerances in an attempt to “gas-proof” the weapon. Those tight tolerances, however, proved to be a problem when mud or other foreign matter got inside the weapon.

The MG 42
The need for a simpler, cheaper, easier-to-maintain alternative was already recognized before World War II started, and three companies were asked to submit designs in February 1937. Surprisingly, the winner was the Metall und Lackierwarenfabrik Johannes Großfuß AG, a company producing pressed and stamped steel components with no weapons manufacturing experience. Werner Gruner, one of the company’s leading design engineers, knew nothing about machine guns when he was given the task of designing one. He attended an army machine gunner’s course to learn about the characteristics of such weapons, and also asked for the input of soldiers who had hands-on experience. The work of the neophyte gunsmith became one of the best machine guns of the war.
 
While the components of the MG 34 were milled, much of the new machine gun, the MG 42, was made of cheap pressed and stamped carbon steel spot welded or riveted together. This not only made production quicker and cheaper, but also reduced wastage from milling. A single MG 42 could be built in 75 man-hours using 61 lb (27.5 kg) of raw materials, as opposed to the MG 34’s 150 man-hours and 108 lb (49 kg) material cost.