Types of Machine Guns
Machine guns are classed as light, medium, or heavy. Both light and medium machine guns shoot a rifle-sized round.
is usually equipped with a shoulder stock and normally has a bipod at the end of the barrel. Some light machine guns are adaptable for mounting on a tripod. A light machine gun is operated by one man. From World War I to the early 1960's the principal American light machine gun was the Browning Automatic Rifle (BAR). (The BAR, despite its name, was a light machine gun.) In 1964 the United States adopted the M-16, a true automatic rifle, and the BAR was retired.
In 1984, the United States began equipping its forces with a new light machine gun, the M-249, or squad automatic weapon (SAW). It uses 5.56-mm ammunition.
The submachine gun, or burp gun, is sometimes classified as a special type of light machine gun even though it lacks the accuracy of a true machine gun. It uses pistol-type ammunition.
is nearly always used as a crew weapon, operated by a gunner and assistant. It may be fired from a tripod or swivel mount and some models are also equipped with built-in bipods. Examples are the .30 caliber water-cooled Browning Machine Gun (now obsolete), the .30 caliber air-cooled Browning (once an infantry weapon but now sometimes used on vehicles), the 7.62-mm (.308 caliber) M-60, and the 7.62-mm (.308 caliber) M-240, the standard infantry medium machine gun of the U.S. Marine Corps since 1995.
The M-240 can fire as many as 950 rounds per minute with an effective range of 1.1 miles (1.8 km). The U.S. Army uses a version of the M-40 as a mounted gun on tanks and other armored vehicles.
The most devastating United States machine gun is the minigun, developed in the mid-1960's. It is capable of firing from 4,000 to 6,000 rounds per minute. The gun has six barrels arranged in a cylinder that rotates, providing fire through each barrel one after another. The gun uses 7.62-mm ammunition. Miniguns are placed on helicopters and slow-moving airplanes for use against enemy ground troops.
is one whose caliber is between that of a rifle and a cannon. The standard American heavy machine gun is the air-cooled .50 caliber Browning. It is generally mounted on tanks or armored personnel carriers; during World War II it was also used on aircraft. United States infantry troops in stationary defensive positions sometimes use the quad-50, a battery of four .50 caliber Brownings whose effect is much like that of light artillery. The United States Mark 19 Model 3.40-mm heavy machine gun is not a true machine gun but an automatic grenade launcher.