Heavy machine gun

A heavy machine gun (HMG) is significantly larger than light, medium or general-purpose machine guns. HMGs are typically too heavy to be man-portable (carried by one person) and require mounting onto a weapons platform to be operably stable or tactically mobile, have more formidable firepower, and generally require a team of personnel for operation and maintenance.

There are two classes of weapons generally defined as HMGs:

• The historical definition refers to machine guns, typically chambered in standard full-power cartridges, that are identified as being "heavy" due to their weight and cumbersomeness, which prevents infantrymen from transporting them on foot. Examples include the Maxim machine gun and M1917 Browning machine gun.
• The modern definition refers to "heavy caliber" machine guns, pioneered by the German Empire's MG 18 TuF which was a Maxim derivative chambered in 13.2×92mmSR fielded near the end of World War I. They are designed to provide increased effective range, penetration and stopping power against vehicles, aircraft and light fortifications beyond the full-power cartridges used in battle rifles and medium or general-purpose machine guns, and far beyond the intermediate cartridges used in assault rifles, light machine guns and squad automatic weapons. HMGs also have more felt recoil than its lighter counterparts. Popular HMG rounds today are the 12.7×99mm, 12.7×108mm and 14.5×114mm cartridges.