The Diamondback Firearms DB15 5.56 NATO semi-automatic rifle is an excellent intermediate level AR-15 for defense, hunting and recreational use. It's built from the ground up right here in the USA. Featuring forged 7075-T6 aluminum receivers, a 16" 4140 chrome-moly free float barrel and a magnetic particle inspected, shot-peened bolt carrier, the DB15 is built to last.