Geissele Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver Group 08-544B is built to deliver dependable performance in a compact, duty-ready package. Featuring an 11.5-inch cold hammer forged barrel with a chrome-lined bore and chamber, this upper is designed for longevity, accuracy, and resistance to heat and fouling under sustained fire. The 1:7 twist rate optimizes stability for a wide range of bullet weights, making it a versatile option for both training and real-world scenarios. This upper includes a 10.5" MK16 Super Modular Rail that offers rock-solid accessory mounting via M-LOK, while keeping the overall weight down. Additional features include a Geissele Airborne Charging Handle, low-profile pinned gas block, and a HUXWRX Flash Hider QD 5.56 for suppressor compatibility. Ideal for law enforcement, tactical shooters, or home defense setups, this upper group embodies Geissele's reputation for durability, precision, and premium components. Caliber: 5.56 NATO Barrel Length: 11.5" Barrel Twist Rate: 1:7 Barrel Construction: Cold Hammer Forged, Chrome Lined Handguard: 10.5" MK16 Super Modular Rail, M-LOK Gas Block: Geissele Pinned Low-Profile Muzzle Device: HUXWRX Flash Hider QD 5.56 Charging Handle: Geissele Airborne Charging Handle Finish: Black Part Number: 08-544B Geissele Automatics Geissele Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver Group 08-544B