Eugene Stoner Eugene Morrison Stoner ( November 22 , 1922 - April 24 , 1997 ) is the man most associated with the design of the AR - 15 . It was adopted by the US military as the M16 . He is regarded by most historians , along with John Browning and Mikhail Kalashnikov , as one of the most successful firearms designers of the 20th century . Eugene Stoner attended high school in Long Beach and afterwards worked for the Vega Aircraft Company installing armament . During World War II , he enlisted for Aviation Ordnance in the U . S . Marine Corps and served in the South Pacific and northern China . In late 1945 he began working in the machine shop for Whittaker , an aircraft equipment company , and ultimately became a Design Engineer . In 1954 he came to work as chief engineer for ArmaLite , a division of Fairchild Engine & Airplane Corporation . While at ArmaLite , he designed a series of prototype small arms , including the AR - 3 , AR - 9 , AR - 11 , AR - 12 , none of which saw significant production . Their only real success during this period was the AR - 5 survival rifle , which was adopted by the United States Air Force . In 1955 , Stoner completed initial design work on the revolutionary AR - 10 , a lightweight ( 7 . 25 lbs . ) selective - fire infantry rifle in 7 . 62 x 51 mm NATO caliber . The AR - 10 was submitted for rifle evaluation trials to the US Army ’ s Aberdeen Proving Ground late in 1956 . In comparison with competing rifle designs previously submitted for evaluation , the AR - 10 was smaller , easier to fire in automatic , and much lighter . However it arrived very late in the testing cycle , and the army rejected the AR - 10 in favor of the more conventional T44 , which would become the M14 . The AR - 10 ' s design was later licensed to the Dutch firm of Artillerie Inrichtingen , who produced the AR - 10 until 1960 for sale to various foreign military forces . At the request of the U . S . military , Stoner ' s chief assistant , Robert Fremont and Jim Sullivan designed the AR - 15 from the basic AR - 10 design , scaling it down to fire the small - caliber . 223 Remington cartridge . The AR - 15 was later adopted by United States military forces as the M16 rifle . After ArmaLite sold the rights to the AR - 15 to Colt , Stoner turned his attention to the AR - 16 design . This was another advanced 7 . 62 mm rifle but used a more conventional piston and a number of stamped parts to reduce cost . This weapon saw only prototype development but adaptation to . 223 resulted in the somewhat successful and often imitated Armalite AR - 18 . Stoner left ArmaLite in 1961 to serve as a consultant for Colt . He eventually accepted a position with Cadillac Gage where he designed the Stoner 63 Weapons System . This was a modular weapons system that could be reconfigured to be a standard automatic rifle , a light machine gun , a medium machine gun , or a solenoid - fired fixed machine gun . The Stoner Weapons System used a piston - operated gas impingement system , though Stoner himself believed direct gas operation was the ideal method for firearms . Once again , Robert Fremont and Jim Sullivan would take a Stoner design and redesign it for the . 223 Remington cartridge , to create the Stoner 63 Weapons System . Stoner worked for TRW by designing the TRW 6425 25 mm " Bushmaster " auto cannon , which was later manufactured by Oerlikon as the KBA . He co - founded ARES Incorporated of Port Clinton , Ohio , in 1972 , but left the company in 1989 , after designing the Ares Light Machine Gun , sometimes known as the Stoner 86 . It was an evolved version of the Stoner 63 . At Ares , he also designed the Future Assault Rifle Concept ( FARC ) . In 1990 , he joined Knight ' s Armament Company ( KAC ) to create the Stoner Rifle - 25 ( SR - 25 ) , which currently sees military service as the United States Navy Mark 11 Mod 0 Sniper Weapon System . While at KAC , he also worked on yet another version of the Stoner Weapons System , called the Stoner 96 . Among his last designs were the SR - 50 rifle and the Colt 2000 .