The Ruger® AR-556® Semi-Auto Rifle with Free-Float Handguard operates with direct-impingement and a rifle-length gas system. The lower receiver comes equipped with a Magpul® MOE® pistol grip and a MOE SL™ 6-position, collapsible buttstock on a Mil-Spec buffer tube. Upper and lower receivers are CNC-machined from 7075-T6 aluminum forgings and Type III hard-coat anodized for maximum durability. An 11'' free-float, M-LOK® handguard features accessory attachment slots at 3:00, 6:00 and 9:00 positions, and a continuous Picatinny rail interface with the flat-top, railed, upper receiver. The upper receiver features a forward assist, dust cover, and brass deflector, while the Ruger® single-stage trigger offers a smooth, crisp break at approximately 4.5 lbs. The bolt carrier and gas key are chrome-plated to provide exceptional resistance to hot gases; and the gas key is securely staked to prevent loosening during extensive fire. The cold hammer-forged steel alloy barrel boasts a 1:8'' twist ratio to maximize accuracy with bullets ranging from 35 to 77 grains, and features an M4 feed ramp, and black Nitride finish for superior corrosion and moisture resistance. A factory-installed Ruger radial-port flash suppressor is attached to the 1/2''x28 threaded barrel, and is easily removed to accommodate aftermarket muzzle devices. The Ruger AR-556 Semi-Auto Rifle comes with one 30-round Magpul® PMAG® detachable box magazine. Made in USA. With improved balance and handling, Ruger AR 556 in .300 AAC Blackout is versatile enough to give you all that you're looking for in a sporting rifle.