The M60 medium/universal machine gun was designed in the late 1940's and its initial design strongly borrows from WW2 German developments - the MG42 belt feeding mechanism and the FG42 gas-driven action. The M60 was adopted by US military in 1950 and served until it was replaced by FN MAG/M240. M60 is a gas-operated, belt-fed, automatic weapon. It features interchangeable barrel, integral folding bipod and provisions to be mounted on tripods and vehicle mounts. M60 was barely adequate to its intended mission, and has some drawbacks: the bipods and the gas chamber were permanently attached to the barrel, so qiuick replacement of the hot barrel in the battle conditions was 'tricky' at least, and required the shooter to war heat-protecting gloves. The barrel should be changed after 200 rounds of the rapid fire. Another drawback (at least, it is known from my sources) was fragility of many of the parts in the operating group. Key among these, and inherent in the design, was the firing pin, which seemed almost guaranteed to break right behind the forward shoulder. The total acceptance troops of the M60 was not too god. But it turned even worse when new, lightened variant of the M60, called M60E3, was introduced. The only positive thing that could be said about M60E3 is that it has non-removable gas chamber that beared the non-removavle bipods, and the new barrel had the carrying handle that also was used to replace the barrel. The "lightening" of the construction dramaticlay decreased the reliability of the gun. The new, light barrel was capable of no more than 100 rounds in rapid fire. 200-300 rounds of the rapid fire without replacing the barrel could simply destroy the barrel. The reliability of the M60E3, used by US MC, was even worse than of original M60, and one of the main reasons the US MC adopted FM MAGs as M240D was wery poor acceptance of the M60E3's among the troops.