In 1970, the U.S. Army designated the light machine gun configuration XM207 and issued it to select Army Special Forces units for evaluation. However, due to its complexity and high maintenance requirements (especially when compared to the new M16), the design was rejected, and the project was dropped in 1971. That same year, Cadillac Gage ceased all production of the Stoner 63. Around 4,000 63 and 63A units were built in total. The Navy SEALs continued to use the Stoner 63 and had officially adopted the Commando version as the Mark 23 Mod 0 machine gun. By the late 1980s the Stoner 63 was completely phased out in favor of the new M249 SAW, and most of the remaining guns were destroyed.