Geissele Super Duty Mod 1 5.56 NATO Upper Receiver Group – 13.9" Barrel, Black

The Geissele Super Duty Mod 1 complete upper receiver group delivers a purpose-built 5.56 NATO platform with a 13.9" barrel configuration. Designed for AR-15 pattern lowers, this upper ships as a complete assembly ready to pair with your mil-spec lower receiver. The 13.9" barrel length allows for a pinned and welded muzzle device to meet 16" overall barrel requirements while maintaining a compact profile.

Constructed with a forged 7075-T6 aluminum receiver and a cold hammer-forged barrel, this upper features Geissele's MK16 M-LOK handguard for direct accessory mounting. The black hardcoat anodized finish provides corrosion resistance for field use. Includes a properly staked and torqued barrel nut, gas system, and bolt carrier group. Confirm your specific build requirements for muzzle device pinning and NFA compliance before installation.

• Caliber: 5.56 NATO
• Type: Complete Upper Receiver Group
• Compatible Lower: AR-15 / Mil-Spec
• Barrel Length: 13.9"
• Material: Forged 7075-T6 Aluminum Receiver, Cold Hammer-Forged Barrel
• Finish: Black Hardcoat Anodized
• Includes: Upper Receiver, Barrel, Gas System, Bolt Carrier Group, Charging Handle, MK16 M-LOK Handguard
• Installation: Drops onto Mil-Spec AR-15 Lower, Requires Pinned Muzzle Device for 16" Compliance