The M60 is a gas-operated, air-cooled, belt-fed, automatic machine gun that fires from the open-bolt position and is chambered for the 7.62 mm NATO cartridge. Ammunition is usually fed into the weapon from a 100-round bandolier containing a disintegrating, metallic split-link belt. As with all such weapons, it can be fired from the shoulder, hip, or underarm position. However, to achieve the maximum effective range, it is recommended that a bipod-steadied position or a tripod-mounted position be used and fired in bursts of 3–5 rounds. The weapon is heavy and difficult to aim when firing without support, though the weight helps reducing the felt recoil. The straight-line layout allowed the operating rod and buffer to run directly back into the buttstock and reduce the overall length of the weapon. The large grip also allowed the weapon to be conveniently carried at the hip. The gun can be stripped using a live round of ammunition as a tool.
In the U.S. military, the M60 has largely been replaced by various versions of the M240 as a medium machine gun, and by the M249 SAW as a squad automatic weapon. However, it remains in use in every branch, as well as some other countries (another major user was Australia); it continues to be manufactured into the 21st century.
The M60 can be used in both offensive and defensive configurations. In the offense, it provides a higher rate of fire, greater effective range, and uses a larger caliber round than the standard-issue U.S. service rifle, the M16 family. In defensive use, the long range, close defensive, and final protective fires delivered by the M60 form an integral part of a unit’s battle plan.
The M60 is effective up to 1,100 meters when firing at an area target and mounted on a tripod; up to 800 meters when firing at an area target using the integral bipod; up to 600 meters when firing at a point target; and up to 200 meters when firing at a moving point target. United States Marine Corps doctrine holds that the M60 and other weapons in its class are capable of suppressive fire on area targets out to 1,500 meters if the gunner is sufficiently skilled.
The M60 is generally used as crew-served weapon, which means that it is usually operated by more than one soldier, in this case two—the gunner and an assistant. The gun’s significant weight makes it difficult to carry and operate by a single soldier. In the modern United States Army Infantry, each soldier will typically carry the much lighter and smaller M16 rifle, while the entire squad will be served by a single, shared M60. The gunner carries the weapon while the assistant carries a spare barrel and extra ammunition in linked belts. The basic ammunition load carried by the crew is 600 to 900 rounds, which at the maximum rate of fire allows for approximately two minutes of continuous firing. In many U.S. units that used the M60 as a squad automatic weapon in Vietnam, every soldier in the rifle squad would carry at least 200 linked rounds of ammunition for the M60, a spare barrel, or both, in addition to his own weapon and equipment. It is fired from various standing positions, and also with the M2 Tripod, the integral bipod, and some other mounts.