The Geissele Super Duty MOD1 5.56 Complete Upper, 16 Inch Barrel, Black (brand part no. 08-548B) is a complete AR-15 upper receiver group chambered in .223 Rem/5.56 NATO, sold with no lower receiver included. Geissele Automatics built the Super Duty MOD1 to bring the company’s next-generation upper technology to market without compromise, aiming for unmatched performance, accuracy, and reliability on a duty or hard-use AR-15. The 16-inch barrel puts this upper in a compact, maneuverable class suited to close-quarters and vehicle-based work, and the whole assembly arrives ready to mate to a compatible AR-15 lower receiver. Every Super Duty MOD1 barrel is cold-hammer-forged, chrome-lined steel cut with a 1:7 twist rate, built to handle sustained fire without losing accuracy.

Key Specifications

• Chambered in .223 Rem/5.56 NATO, compatible with both cartridges.
• Runs a 16-inch barrel, sized for a compact, maneuverable AR-15 build.
• Finished in Black for a distinct appearance and consistent Geissele quality control.
• Barrel finished in Black Teflon for corrosion resistance and heat tolerance.
• Sold as a Complete upper receiver group, ready to mate to a compatible AR-15 lower.
• Measures approximately 30.35 inches overall as an assembled upper receiver group.
• Classified as an Upper product type, with no lower receiver, BCG-to-lower fitment, or magazine included.

Frequently Asked Questions

Does this upper include a lower receiver? No, this is an upper receiver group only; it ships without a lower receiver and must be mated to one separately.

Is a 16-inch upper regulated as a short-barreled rifle? No — sold alone as an upper receiver group with no lower or stock attached, it is not a regulated firearm; a barrel under 16 inches only triggers SBR/NFA rules once assembled onto a lower receiver with a shoulder stock.

What caliber does this upper run? It is chambered in .223 Rem/5.56 NATO.

Buy the Geissele Super Duty MOD1 5.56 Complete Upper, 16in

Drop a next-generation Geissele upper onto a compatible AR-15 lower for a duty-grade build without compromise. Browse Schaefer Defense’s AR-15 uppers selection and order from our Lubbock, Texas gun shop — we’ll get it out to you as soon as it’s ready to ship.