Geissele Automatics Super Duty MOD1 Complete AR-15 Upper Receiver - 5.56 - 13.9" P/W

The Geissele Automatics Super Duty MOD1 Complete AR-15 Upper Receiver in 5.56 NATO pairs a 13.9" cold hammer forged, chrome-lined barrel with Geissele's Reliability Enhanced bolt carrier group and a suppressor-ready HUXWRX Flash Hider-QD.

Features:

• 13.9" cold hammer forged, chrome-lined barrel, 1:7 twist
• Mid-length gas system with Geissele Super Compact Gas Block
• HUXWRX Flash Hider-QD, suppressor-ready, pinned and welded to 16" legal length
• 12.9" Geissele SMR MK16 free-float M-LOK handguard, center-tab mated
• Geissele Reliability Enhanced bolt carrier group, Nanoweapon coated
• Geissele Stressproof bolt, Carpenter 158+, HPT and MPI tested
• Geissele Airborne charging handle
• Super Duty upper receiver with cam pin cutout

The Nanoweapon-coated Reliability Enhanced BCG pairs a staked gas key with an advanced-steel cam pin for improved feeding, while the Stressproof bolt is forged from Carpenter 158+ and HPT/MPI tested. The 12.9" SMR MK16 handguard's center-tab mounting keeps the rail from rotating under load.

Because this 13.9" barrel measures under 16", this complete upper is intended only for an AR pistol or a legally registered short-barreled rifle — attaching it to a standard rifle lower without the correct configuration violates federal law.

Geissele Automatics built its reputation on the Hi-Speed National Match trigger, later adopted by U.S. Special Operations for a select-fire variant, and now applies that same quality control to complete upper receivers for warfighters, competitors, and civilian shooters alike.