page_title: Medium machine gun
section_title: Early 20th century: medium, heavy and light
hierarchical_section_title: Medium machine gun / History / Early 20th century: medium, heavy and light
caption_attribution_description: English: MARINE CORPS RIFLE RANGE, LEWIS MACHINE GUN TESTS
context_page_description: A medium machine gun, in modern terms, usually refers to a belt-fed automatic firearm firing a full-powered rifle cartridge.
context_section_description: Many new designs were developed, some powered by air or recoil, or a combination of the two (e.g., the Colt 1895 and M1895, Hotchkiss M1909, PM M1910, Fiat–Revelli Modello 1914, Fiat–Revelli Modello 1935, Breda M37, and Breda 38). Also, instead of the rather heavy water jacket, new designs introduced other types of cooling, such as barrel replacement, metal fins, and/or heat sinks or some combination of all of them.
  Machine guns then diverged into heavier and lighter designs. The later model water-cooled Maxim gun and its derivatives (the MG 08 and the Vickers gun, as well as the American Browning Model 1917 machine gun), were all substantial weapons. The .303 inch Vickers, for example, weighed 33 lb (15 kg) alone and on its tripod mount the total weight was 50 lb (22.7 kg). The heavier designs could, and in some cases did, literally fire for days on end. The need was to be able to cut down, potentially, thousands of charging soldiers. The heavy machine gun was mounted on a tripod and was often water-cooled; a well-trained and well-supplied crew could fire for hours on end. Carefully positioned heavy machine guns could stop an attacking force before they reached their objectives.
  The first machine guns in use before World War I covered a wide range of characteristics. In addition to these heavier designs, there were also a number of lighter types. During the same period, a number of new air-cooled designs were developed that, instead of weighing well over 30 lb (15 kg), were lighter and more mobile. In World War I, they were to be as important as the heavier designs, and were used to support squads and infantry on the move, on aircraft, and on many types of vehicle, including some tanks. The two that would become critical were new medium and light machine guns. The new medium machine guns offered less, or more difficult-to-use, cooling than the heavier designs, but more than the lightest.
  Light machine guns were introduced as lighter, more portable automatic weapons. They still fired the same full-power rifle caliber ammunition, but used lighter barrels without extra cooling and were fired from a bipod. Light machine guns were not intended to be fired for extended periods of time. The lightest of the new designs were not capable of sustained fire, as they did not have extra cooling features and were fed from a comparatively small magazine. Essentially a machine rifle with a bipod, weapons like the Chauchat or the Madsen 1902 were the most mobile, but were made for single and burst fire. These were used in assaults to great effect by infantry, but were less effective in vehicle-mounted and other applications.
  The medium designs offered greater flexibility, either using a bipod and being used like lighter designs, or being put on a tripod, or on heavier mounts. The Hotchkiss Mark I (e.g. Benét–Mercié M1909) was a 27.6 lb (12.2 kg) MG that normally used a mini tripod and linkable 30-round strips or in vehicles, but there was also a belt-fed version of it. Not be confused with heavier Hotchkiss models (such as the M1914), the design proved a useful intermediate and would serve even to the end of World War II in some jobs. The design would be followed by lighter machine rifles and better medium types. They also shared a common characteristic: they fired full power rifle caliber ammunition such as 8mm Mauser or .30-06 Springfield.
  The Lewis gun, which weighed 27 lb (12.3 kg), was commonly used with a 47-round drum and bipod; it was used on the move in support of squads, and on vehicles and aircraft as well, or on a tripod (either for anti-aircraft use, or to fill in for a heavier MG). What made it very useful was that it was significantly lighter than water-cooled weapons, but could fire nearly as much due to a very large cooling assembly. These sort of multi-purpose machine guns, would be further developed, and later given names like Universal Machine gun or general-purpose machine gun, and would eventually supplant the water-cooled designs. Later designs have mostly switched to fast barrel-replacement as an alternative to co
caption: Lewis gun training, 1917
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