The Stoner 63 is a 5.56×45mm NATO modular weapon system. Using a variety of modular components, it can be configured as an assault rifle, carbine, top-fed light machine gun, belt-fed squad automatic weapon, or as a vehicle mounted weapon. Also known as the M63, XM22, XM23, XM207 or the Mk 23 Mod 0 machine gun, it was designed by Eugene Stoner in the early 1960s. Cadillac Gage was the primary manufacturer of the Stoner 63 during its history. The Stoner 63 saw very limited combat use by United States forces during the Vietnam War. A few were also sold to law enforcement agencies. History Development Soon after leaving ArmaLite, Eugene Stoner, one of the United States' most prolific modern military small arms designers, responsible for the design of the ArmaLite AR-15/M16 assault rifles, ArmaLite AR-10 battle rifle and Armalite AR-7 survival rifle, among others, devised a concept for a modular weapon that would be built around a common receiver and certain interchangeable components and could be transformed into a rifle, carbine or various machine gun configurations by simply fitting the appropriate parts to the basic assembly. Stoner managed to solicit the help of Howard Carson, in charge of Cadillac Gage's West Coast plant in Costa Mesa, California (where Armalite was also located), in convincing the company's president, Russell Baker, of the feasibility and commercial potential of his new weapons system. Russell obliged and Cadillac Gage (a subsidiary of the Ex-Cell-O Corporation) established a small arms development branch in Costa Mesa. Stoner then recruited his two principal aides at Armalite: Robert Fremont and James L. Sullivan (who would later design the Ultimax 100 light machine gun for the Chartered Industries of Singapore). The first working prototype was chambered in 7.62×51mm NATO and completed in 1962. It was designated the Stoner M69W (for no other reason than when turned upside down it reads the same, symbolizing Stoner's vision of a fully invertible receiver). The follow-up design, called the Stoner 62, also chambered in 7.62×51mm, was intended for mass production. However, the design team decided to focus on the 5.56×45mm small caliber high-velocity cartridge, as it appeared the new round was gaining mainstream military approval. Eugene Stoner had previously worked with the cartridge when he designed the AR-15. The weapon system using the smaller cartridge was known as the Stoner 63. The first models were produced in February 1963. The Costa Mesa facility