The Geissele Super Duty MOD1 Complete Upper (brand part no. 08-545B) is a 12.5-inch, 5.56 NATO complete upper receiver group built to mount directly on any mil-spec AR-15 lower without additional parts. Geissele designed the Super Duty MOD1 as a next-generation upper for the platform, combining duty-grade materials and manufacturing with a flat-top rail for optics mounting. It is finished in black and built to the same standard Geissele applies across its Super Duty line: consistent accuracy and reliability under hard use.

Key Specifications

• Chambered in .223 Remington/5.56 NATO.
• Barrel measures 12.5 inches.
• Sold as a complete upper, ready to mount on any mil-spec AR-15 lower.
• Flat-top rail for mounting optics.
• Part of Geissele’s Super Duty MOD1 upper lineup.
• Built as a duty-grade, next-generation AR-15 upper.
• Finished in black.
• Engineered for consistent accuracy and reliability under hard use.

Frequently Asked Questions

Does this upper come complete? Yes, it is a complete upper receiver group that mounts directly to any mil-spec AR-15 lower.

What caliber is this upper chambered in? It is chambered in .223 Remington/5.56 NATO.

Buy the Geissele Super Duty MOD1 12.5-inch Complete Upper

A duty-grade upper is only as good as the receiver, barrel, and rail working together, and Geissele built the Super Duty MOD1 to hold up to that standard. Browse more AR15 uppers from Geissele Automatics and order it from our Lubbock, Texas gun shop as soon as it’s ready to ship.