The M53 155 mm self propelled gun was designed to provide long-range fire support to allied positions while keeping pace with mechanized formations cross-country. It was adopted in 1952 for both the Army and Marine Corps, all made by Pacific Car & Foundry Company. As the M55 was the same vehicle designed around a different howitzer, M53s were later standardized as M55s. Production ceased in 1956 and M53s were used in Vietnam by the USMC until around 1969, but remained in service for many more years with some NATO countries.