M73 7.62mm Machine Gun
M219 7.62mm Machine Gun
The M73, M73A1, and M219 7.62mm machine guns are lightweight, air-cooled, metallic link belt fed from either right or left side, designed as a coaxial gun for tanks and 7.62mm fire power on lighter armored vehicles. All have short receivers, are recoil operated with a gas assist to boost recoil and are designed with a quick change barrel with fixed headspace. The cycle of operation and functioning is initiated from the retracted (seared) position of the barrel extension assembly. These machine guns can be easily disassembled. Ammunition can be fed from either the left or the right side for flexibility in mounting. The M73 has a rate of fire of 450-500 rounds per minute.
The design requirements for the weapon were first outlined at a conference at Fort Knox, Kentucky in 1950. A weapon was needed to fit between the breech ring of the M68 cannon and the mantlet on the M60 tank. Research and development work began at Springfield Armory first in February 1951 and was stopped in June 1953 before resuming in May 1956. Four machine guns were considered, the T197, T198, T199, and T200. Of these the T197, designed by Richard Colby of Springfield Armory, was selected for further development. The weapon was also under development concurrently with Aircraft Armament, Inc.'s T175, a similar short recoil weapon being developed at Springfield Armory, but in .50 caliber, which was eventually standardized as the M85.
A product improved T197E1 was quickly followed by a further refined T197E2 in February 1958. What had proved to be a troublesome development ended when the T197E2 was type standardized as the M73 in May 1959. The M73 was prone to jamming and experienced numerous other malfunctions. Following issues in the initial production weapons, Springfield Armory produced a booster modification, which included new case carrier grips, spring and link (designed to prevent cases separating during feeding and extraction), a new booster, and a barrel with an extended stillite liner. All weapons produced after January 1963 incorporated these improvements.
A variant of the M73, designated as the M73C, was modified for use as a flexible machine gun by addition of sights and a pistol grip trigger. The M73C was mounted on the XM132 tripod mount, which was a variant of the M2 tripod with an adapter specifically for the M73C. A modified version of the basic fixed variant was designated as the XM161 in 1966.
More major improvements were developed in order to try and correct the deficiencies in the M73 machine gun. The result was the product improved M73E1. The M73E1, produced by General Electric, was subsequently type standardized as the M73A1. The M73 and M73A1 had a number of differences. The first of these was the replacement of the stationary studs, fixed on both sides of the receiver, with a milled slot in either side of the M73A1 to accommodate the movable charger mounting stud. The ejector shield on the bottom of the M73 receiver was eliminated on the M73A1. The M73A1 was equipped with a spent case deflector plate on the lower right side of the receiver. The feed tray assembly was redesigned by adding fixed ejectors to the bottom rear of the tray. The lever was also redesigned assembly by eliminating the case grip assembly and link assembly, and by redesigning the lever itself. The extractor, rammer, and rammer assembly and the buffer assembly were all redesigned as well.
In the early 1970s, additional new cams were added to the receiver, which altered the timing of extraction, ejection and ramming, and reduced the incidence of stoppages. These cams meant that certain components were no longer interchangable between the M73A1 and the M73, and the decision was made to redesignate the weapon as the M219. With the exception of the cams, the M73A1 and M219 were essentially identical. The M219, produced by Rock Island Arsenal, incorporated this new change and the other M73A1 improvements. As of 1972, it was planned that all M73, M73E1 and M73A1 models would be changed at time of overhaul to the M219 configuration.
However, despite the continuing efforts to improve the machine gun, problems encountered by the Israelis during the 1973 Yom Kippur war caused the US Army to seek a replacement. Considerable study and trade-offs led the Army to adopt the Belgian Fabrique National MAG medium machine gun as the M240 machine gun in 1977.
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