Geissele 08-545S Super Duty MOD1 5.56 NATO 12.5" 1:7" CHF Chrome Lined Bbl DDC Complete Upper ReceiverThe Geissele Super Duty MOD1 5.56 NATO Complete Upper Receiver Group 08-545S features a 12.5-inch, 1:7 twist chrome-lined barrel that is both pinned and welded. This Geissele 08-545S high-performance upper is designed for durability and precision, making it a reliable choice for serious shooters. The barrel's chrome lining enhances longevity and resistance to wear, while the pinned and welded configuration ensures compliance with firearm regulations. Finished in DDC, this complete upper receiver group is ideal for upgrading or customizing your firearm..yellow-box p {font-size:16px}.special-tab {color: #FFFFFF}.yellow-box ul li {font-size: 16px;}The Geissele Super Duty MOD1 Complete Upper Receiver offers top-tier components for a custom AR build. Geissele Super Duty MOD1 Upper Receiver is precision-machined, cold hammer forged barrel is made from high-quality steel, coated with manganese phosphate and chrome lining for durability against the elements. The HUXWRX Flash Hider-QD 556 muzzle device enhances performance and is suppressor-ready. The included Reliability Enhanced Bolt Carrier Group features Nanoweapon coating, properly staked gas key, and a cam pin machined from H13 tool steel for corrosion and wear resistance. Extended upper rails improve stability and feeding reliability, while the Stressproof Bolt offers superior strength and fatigue resistance. The updated MK16 Super Modular Rail ensures a secure fit for a variety of optics, including iron sights, red dots, scopes, and thermal/night vision devices. Features of the Geissele Super Duty MOD1 Upper ReceiverPrecision 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 12.5" 1:7" CHF Chrome Lined Bbl DDC Complete Upper Receiver Group 08-545S