Upper Receiver Assembly 308, Black Anodized Gen 4 Barrel: - Length: 14.5" - Match grade barrels fluted to reduce weight and dissipate heat. - 4150 Mil-B-11595E chromoly alloy. - Corrosion resistant nitride heat-treated 1:10. - POF-USA triple-port muzzle devices. - POF-USA oversized heat-sink barrel nut. - 7.62x51 mm NATO (.308 Winchester) chamber. - E dual-extraction chamber technology (GEN 4 ONLY). Method of Operation: - Semi-auto (P308) rotating bolt, short-stroke gas piston system. - Corrosion resistant nitride heat-treated gas piston system consisting of a single piece gas block, gas plug, gas piston, and operating rod. - Multi-position regulating gas system with normal, suppressed, and bolt-action (off) operating modes. Bolt & Carrier: - Nickel plated bolt carrier with integrated bolt carrier key. - POF-USA roller cam pin with chrome plated stem and NP3 roller. - Chrome plated bolt. Upper Receiver: - POF-USA patented Modular Railed Receiver (M.R.R.); free-floating monolithic rail system. - Billet machined 7075-T6 aircraft aluminum alloy. - 2-piece upper receiver. - Black anodized billet charging handle. - 6 lbs - Overall Length: 23" - 11" M.R.R. Handguard - POF-USA free-floating modular "M" Rail aluminum handguard. - Two 5-slot and one 12-slot modular rail sections for bottom, sides, or top of "M" Rail. - Black Anodized Manufacturing: - All raw materials, heat-treats, platings/coatings, accessories, and component parts on our weapon systems are made 100% through U.S. owned and operated steel mills and manufacturers.