Diamondback Firearms DB15300 rifles are made entirely in the USA, starting with the tried-and-true, U.S. Military-proven gas-impingement system and using only the highest quality components machined in Diamondback's CNC facility. The DB15300 fires the popular .300 AAC Blackout round, a new leap forward in ammunition technology. Every DB15300 stars with a 16" 4140 chrome-moly, M4 contour barrel that's free-floated. Both the upper and lower receiver are constructed from forged 7075 T6 aluminum and the upper has an A2-style flat-top with a full-length top rail that provides nearly endless optics mounting options. An aluminum modified four rail is standard as well for all of your other accessory mounting needs. The ATI Strikeforce stock has an aluminum civilian buffer tube assembly and is collapsible for length-of-pull adjustments. A2 flash hider. 30-round magazine. 1 in 9" twist.