Geissele Super Duty MOD1 5.56 NATO 13.9" 1:7" CHF Chrome Lined Pinned & Welded Barrel Black Complete Upper Receiver Group 08-546B is a duty-grade upper built to exceed expectations in both reliability and performance. Featuring a 13.9-inch cold hammer-forged barrel made from mil-spec steel and chrome-lined for maximum durability. The 1:7 twist rate allows it to stabilize a wide range of bullet weights, from light varmint rounds to heavy-duty defensive loads.

This upper includes Geissele’s Nanoweapon-coated Reliability Enhanced Bolt Carrier Group, offering exceptional resistance to wear and corrosion. The ambidextrous Airborne Charging Handle provides improved manipulation under stress, while the MK16 Super Modular Rail delivers a slim, rigid platform with extensive M-LOK real estate for accessories. Finished in a Type III hardcoat anodized black, this upper is optimized for professional-grade performance in a highly versatile barrel length.

• Caliber: 5.56 NATO
• Barrel Length: 13.9"
• Barrel Profile: Geissele Profile
• Barrel Construction: Cold Hammer Forged (CHF)
• Barrel Finish: Chrome Lined
• Barrel Twist Rate: 1:7
• Bolt Carrier Group: Geissele Reliability Enhanced BCG (Nanoweapon-coated)
• Charging Handle: Airborne Charging Handle
• Handguard: MK16 Super Modular Rail
• Receiver Finish: Type III Hardcoat Anodized, Black
• Part Number: 08-546B