The M73 was standardized in 1959 following a lengthy and troublesome development program which was suspended between 1953 and 1956. The M73 was prone to jamming and experienced numerous other malfunctions. The M73 was developed specifically as a NATO caliber fixed tank machine gun. The M73 had a quick-change barrel. Ammunition could be fed from either side for flexibility in tank mounting. The M73 had a rate of fire of 450-500 spm. The M73C is an M73 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 .30 cal. M2 mount with an adapter to fix the M73C.To correct the deficiencies in the M73 machine gun, a product improved M73E1 was developed. One of the principal improvements was its simplified ejection system. The M73E1 was standardized and type classified as the M219 machine gun, since its parts were not interchangable with the M73. Despite continuing efforts to improve the machine gun, problems encountered by the Israelis during the 1973 Yom Kippur war caused the 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.