Geissele 08-544B Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver GroupGeissele 08-544B Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver GroupThe Geissele Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver Group 08-544B delivers exceptional performance and durability for your custom AR build. The Geissele 08-544B ensures precise accuracy and resilience in any environment, featuring an 11.5 CHF Chrome barrel with a 1-7 twist rate and a nano weapon-coated HUXWRX Flash Hider-QD muzzle device. With Geisseles Reliability Enhanced Bolt Carrier Group, equipped with advanced coatings and materials, including a stress-proof bolt machined from Carpenter 158+ bar stock, this Geissele Super Duty MOD1 Receiver group guarantees reliable operation and longevity. Paired with the updated MK16 Super Modular Rail, meticulously aligned to prevent rotation, it provides ample space for optics and accessories, making it the ultimate choice for discerning shooters seeking uncompromising performance and reliability. Features of the Super Duty MOD1 Complete Upper Receiver: Precision machined, cold hammer forged barrelHUXWRX Flash Hider-QD 556 muzzle deviceGeissele own Reliability Enhanced Bolt Carrier GroupGeissele Stressproof BoltAirborne Charging HandleUpdated MK16 Super Modular Geissele Super Duty MOD1 5.56 NATO 11.5" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver Group 08-544B