Geissele Automatics Super Duty Mod 1 .300 Blackout AR-15 Complete Upper Receiver – 8″ – Black
The Geissele Super Duty Mod 1 8″ .300 Blackout Complete Upper is a turnkey, hard-use upper built for compact performance and reliability. It pairs a cold-hammer-forged, chrome-lined 1:7 barrel with Geissele’s Phased Array Tri-Port gas system, tuned for a pistol-length configuration, for consistent function under demanding conditions. This upper ships complete with a Nanoweapon Reliability-Enhanced BCG (Stressproof bolt), Airborne Charging Handle, and a HUXWRX Flash Hider, QD-threaded 5/8×24, making it ready to run out of the box.
The included 7″ Super Modular Rail MK16 with center tab provides a rigid, lightweight mounting platform, and the package also includes a braided buffer spring and H1 buffer combo. Built and assembled by Geissele Automatics in Pennsylvania, this Mod 1 upper is an excellent choice for compact .300 BLK builds that require durability and repeatable performance.
Features
- Complete 8″ .300 BLK upper with BCG, charging handle, and muzzle device
- CHF, chrome-lined barrel with 1:7 twist
- Phased Array Tri-Port gas system with pistol-length configuration
- Nanoweapon Reliability Enhanced BCG with Stressproof bolt
- Geissele Airborne Charging Handle included
- 7″ MK16 Super Modular Rail with center tab
- HUXWRX Flash Hider-QD (5/8×24) included
- Includes braided buffer spring + H1 buffer combo
Specifications
- Caliber: .300 Blackout
- Barrel Length: 8″
- Barrel Profile: Medium
- Barrel Finish: Mag Phosphate
- Twist Rate: 1:7
- Gas System: Pistol-length (custom configuration)
- Handguard: 7″ Super Modular Rail MK16 (center tab)
- Muzzle Device: HUXWRX Flash Hider-QD, 5/8×24
- Overall Length: 17 1/8″
- Weight: Approx. 3.3 lb
- BCG / Charging Handle: Included
- Manufacturer: Geissele Automatics (North Wales, PA, USA)








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