
A light machine gun (LMG) is a light-weight
machine gun designed to be operated by a single
infantryman, with or without an assistant, as an
infantry support weapon. LMGs firing
cartridges of the same
caliber
In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore ma ...
as the other
riflemen of the same
combat unit are often referred to as
squad automatic weapons.
Characteristics
While early light machine guns fired
full-powered rifle cartridges, modern light machine guns often fire smaller-caliber
rifle cartridges than
medium machine guns – generally the same
intermediate cartridge
An intermediate cartridge is a rifle/carbine cartridge that has significantly greater power than a pistol cartridge but still has a reduced muzzle energy compared to fully powered cartridges (such as the .303 British, 7.62×54mmR, 7.92×57mm ...
fired by a service's standard
assault rifle – and are usually lighter and more compact. Some LMGs, such as the Russian
RPK, are modifications of existing designs and designed to share the same ammunition. Adaptations to the original rifle generally include a larger magazine, a heavier barrel to resist overheating, a more robust mechanism to support sustained fire and a bipod.
A light machine gun is also defined by its usage as well as its specifications: some machine guns – notably
general-purpose machine guns – may be deployed either as a light machine gun or a medium machine gun. Deployed on a tripod and used for sustained fire, it is a medium machine gun; if deployed with a
bipod with the operator in a prone position and firing short bursts, it is a light machine gun.
Light machine guns are also designed to be fired from the hip or on the move as a form of
suppressive fire intended to
pin down the enemy.
Marching fire is a specific tactic that relies on this capability.
Lighter modern LMGs have enabled them to be issued down at the
fireteam level, with two or three at the section/squad level.
Ammunition feed
Many light machine guns (such as the
Bren gun
The Bren gun was a series of light machine guns (LMG) made by Britain in the 1930s and used in various roles until 1992. While best known for its role as the British and Commonwealth forces' primary infantry LMG in World War II, it was also use ...
or the
M1918 Browning Automatic Rifle) were
magazine
A magazine is a periodical publication, generally published on a regular schedule (often weekly or monthly), containing a variety of content. They are generally financed by advertising, purchase price, prepaid subscriptions, or by a combinatio ...
-fed. Others, such as the
Hotchkiss M1922, could be fed either from a
belt/
strip or from a
box magazine. Modern light machine guns are designed to fire smaller caliber rounds and, as such, tend to be belt-fed (from a
container attached to the gun) or from a detachable high-capacity
drum magazine
A drum magazine is a type of high-capacity magazine for firearms. Cylindrical in shape (similar to a drum), drum magazines store rounds in a spiral around the center of the magazine, facing the direction of the barrel. Drum magazines are contrast ...
, but some, such as the
FN Minimi, will also accept standard rifle magazine feeding as an auxiliary measure when belted ammunition has been exhausted.
History
In 1903, French military theorists noticed that the
heavy machine guns of the day were of little use in infantry assaults. They determined that "the machine gun must learn to walk".
They researched the possibility of a light machine gun which could be carried by troops. A
marching fire tactic was theorised, using incidental suppressive fire, with the advancing troops considered a deadlier threat than the un-aimed bullets, causing the enemy to fall back. The prototype guns were not approved for production, and none were in service when
World War I began.
[ The French quickly brought the prototypes to mass production to boost the firepower of advancing infantry.
By the end of World War II, light machine guns were usually being issued on a scale of one per fire team or ]squad
In military terminology, a squad is among the smallest of military organizations and is led by a non-commissioned officer. NATO and US doctrine define a squad as an organization "larger than a team, but smaller than a section." while US Army do ...
, and the modern infantry squad had emerged with tactics that were built around the use of the LMG to provide suppressive fire.
Selected examples
The following were either exclusively light machine guns, had a light machine gun variant or were employed in the light machine gun role with certain adaptations.
See also
* Medium machine gun
* Heavy machine gun
* Automatic rifle
* Squad automatic weapon
* General-purpose machine gun
* Assault rifle
References
{{Reflist
*
Danish inventions