The M73 was a 7.62mm NATO machine gun that was adapted for tank operations, created in a few different variants, including the M73C which was designed for infantry use but never entered service, and the M73A1 (also known as the M219) which was designed with improved ejectors which were intended to solve the M73’s issue with jamming. 

The first M73s were developed as replacements for the tank-mounted M1919 variants, the M1919A4E1 and M1919A5. The first variants were air-cooled, recoil-operated platforms that were belt-fed; a unique feature of the platform is that it can be fed from either the right or the left. It was also outfitted with a quick change barrel that could easily be swapped out if the barrel overheated due to periods of intense, sustained fire. 

Although the M73 was prone to jamming (resulting in the development of variants listed above) it was capable of reaching rates of fire of about 600 rounds per minute and had an effective firing range of just within 1,000 yards. Mounted on M48 Patton and M60 Patton Main Battle Tanks (MBTs) these machine guns saw limited use in Vietnam, though they were eventually replaced by the M60E2 and M240 Machine Guns.