Heavy machine gun

There are two classes of weapons generally defined as HMGs: The term originally referred to the generation of machine guns which came to prominence in the lead up to and during World War I.

[3] Pioneered by the German Empire's 13.2×92mmSR caliber MG 18 TuF (Maschinengewehr 18 Tank und Flieger, 'Machinegun 18 Tank and Aircraft') during World War I, these weapons are designed to provide increased range, penetration and destructive power against vehicles, buildings, aircraft and light fortifications beyond the standard rifle calibers used in medium or general-purpose machine gun, or the intermediate cartridges used in light machine guns.

This class of machine gun came into widespread use during World War II, when the M2 was used widely in fortifications, on vehicles and in aircraft by American forces.

The heavier designs could, and in some cases did, fire for days on end, mainly in fixed defensive positions to repel infantry attacks.

These machine guns were typically mounted on tripods and were water-cooled, and a well-trained crew could fire nonstop for hours, given sufficient ammunition, replacement barrels and cooling water.

Essentially machine rifles with a bipod, weapons like the Lewis Gun, Chauchat and the Madsen were portable by one soldier, but were made for single and burst fire.

An example was the Hotchkiss M1909 machine gun weighing 27.6 lb (12.2 kg) fitted with a mini-tripod and using linkable 30-round ammunition strips, but there was also a belt-fed version.

This was possible in part because a heavy, static MG position was not a very effective tactic in vehicle-centered warfare, and the significantly lighter air-cooled designs could nearly match the capabilities of the water-cooled versions.

These are typically mounted on ships and helicopters because of their weight and large ammunition requirements due to their extremely high rate of fire.