The Windham Weaponry R18FSFST is a semi-automatic gas impingement system rifle. It features hardcoat black anodized finish forged 7075-T6 aircraft aluminum lower and flat top upper receivers in addition to a 4150m chrome moly vanadium steel 18 chrome-lined fluted barrel with A2 flash suppressor. Other features include a Carpenter 158 steel bolt integral trigger guard KeyMod 15 handguard six-position telescoping buttstock and Hogue overmolded pistol grip. Details Action Semi Auto - Caliber .308 Win - Capacity 201 - Finish Hardcoat Black Anodize - Bolt Material Carpenter 158 Steel - Receiver Flat Top Upper - Receiver Material 7075 T6 Aircraft Aluminum - Stock 6 Position Telescoping Buttstock - Grip Hogue Overmolded - Safety Manual Lever with Indicator Markings - Twist 110 - Barrel 18 Fluted Chrome Lined wA2 Flash Suppressor - Overall Length 39.5 - Weight 8.05 lb