Geissele Super Duty MOD1 | 5.56 Complete Upper

The Geissele Super Duty MOD1 Complete Upper is a 5.56 NATO upper receiver assembly designed for AR-15 platform rifles, available in 11.5", 14.5" (pinned & welded), and 16" configurations. Each upper features a cold hammer forged, chrome-lined barrel paired with a free-float MK16 handguard, offering a complete solution for users building or upgrading a rifle. The upper is compatible with standard mil-spec AR-15 lower receivers and includes key components such as a bolt carrier group and ambidextrous charging handle.

This upper assembly incorporates a tuned gas system matched to each barrel length, along with a low-profile gas block and included muzzle device. Additional features include a coated bolt carrier group for wear resistance, a forged bolt, and a modular rail system with QD sling attachment points. This complete upper is configured for use with standard 5.56 NATO ammunition across a range of shooting applications.

Specifications

• Caliber: 5.56 NATO
• Barrel lengths available: 11.5", 14.5" (pinned & welded), 16"
• Barrel material: Cold hammer forged, chrome-lined, chrome moly vanadium steel
• Twist rate: 1:7
• Receiver: AR-15 upper with cam pin cut-out
• Handguard: Geissele MK16 free-float rail
  • 10.5" (11.5" barrel)
  • 13.5" (14.5" barrel)
  • 15" (16" barrel)
• Gas system:
  • 11.5" – Carbine length
  • 14.5" – Mid-length
  • 16" – Extended/Geissele length
• Gas block: Low-profile compact gas block
• Bolt carrier group: Included, coated for wear and corrosion resistance
• Bolt: Carpenter 158 steel (enhanced design)
• Charging handle: Ambidextrous (Airborne Charging Handle)
• Muzzle device: HUXWRX Flash Hider-QD (1/2x28 thread)
• Weight:
  • 11.5" – Approx. 3 lbs 8 oz
  • 14.5" – Approx. 4 lbs 3 oz
  • 16" – Approx. 4 lbs 5 oz
• Finish options: Black