The M60 machine gun was designed in the late 1940's and its initial design strongly borrows from WW2 German developments. The M60 was adopted by US military in 1950 and served until it was replaced by FN MAG/M240. M60 is a gas-operated, firing from an open bolt, belt-fed, automatic weapon. It features interchangeable barrel, integral folding bipod and provisions to be mounted on tripods and vehicle mounts. The M60 is considered 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. Unlike the M240 variants replacing it, the M60 can be accurately fired at short ranges from the shoulder due to its design. The weapon is heavy and difficult to aim when firing without support, though the weight helps reduce 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 M60's gas operation is unique, and drew on technical advances of the period, particularly the White "gas expansion and cutoff" principle also exploited by the M14 rifle.

The M60E4 is a further improvement over the M60E3, developed during early 1990s by Saco Defence. Key improvements are the introduction of three styles of barrels (long / standard, short and assault), and an improved belt feed with greater pull force for improved belt lift capability. In limited use by the US Navy (mostly Special Operations forces) designation Mk.43 mod.0 and mod.1. The mod.1 differs from mod.0 by having feed cover with integral Picatinny rail, plus a set of similar rails is added to the handguard, and integral forward pistol grip is replaced by removable vertical grip attached to the rail.