Geissele 08-553B Super Duty MOD1 .300 BLK 8" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver GroupThe Geissele Super Duty MOD1 .300 Blackout 8" Upper 08-553B is a premium AR-15 upper designed for compact or suppressed setups. It features an 8" cold hammer forged, chrome-lined barrel with a 1:7 twist for durability and accuracy. TheGeissele 08-553B upper includes Geissele’s enhanced bolt carrier group with a Nanoweapon-coated Carpenter 158+ bolt and a precisely tuned gas system for reliable performance. Also included are the Airborne Charging Handle, MK16 Super Modular Rail for accessory mounting, and a HUXWRX QD flash hider compatible with FLOW suppressors. It typically retails around $1,260 and may be subject to export restrictions..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 .300 BLK 8" 1:7" CHF Chrome Lined Bbl Black Complete Upper Receiver Group 08-553B