<human>:  Who designed the Armalite AR-15?
<bot>: The AR-15 was designed by Eugene Stoner, who also designed the M1 Garand. Stoner was a firearms designer who worked at the ArmaLite company, and he was inspired to create the AR-15 after seeing a demonstration of a new rifle in a military magazine. The AR-15 was the first mass-produced semi-automatic rifle, and it has been used by the US military since the Vietnam War.