The Geissele Super Duty MOD1 Upper (Complete) features the latest in weapon technology factory made by Geissele Automatics. This 11.5” complete upper chambered in 5.56mm features a nanoweapon-coated HUXWRX Flash Hider-QD muzzle device mounted to an 11.5” Manganese Phosphate coated, CHF, Chrome Lined 1-7 twist barrel. Geissele barrels are precision machined and cold hammer forged in the USA. The carbine length gas tube and Geissele Super Compact Gas Block with bomb-proof installation ensures reliability and optimal performance in extreme conditions.

This is a Geissele Factory upper.

The barrels are precision machined and cold hammer forged. The carbine length gas system is perfect for the 11.5" barrel, and includes a Geissele gas Block installed at the factory with both lower set screws and a through the barrel pin.  This is something Geissele has been doing since 2018.  Is it necessary? No.  Extra protection from a gas block moving, which was never going to move in the first place, but something about the Geissele name has that German sound to it, that causes the entire firm to over-engineer, like Mercedes.

The newly designed 10.5” Super Modular Rail MK16 mates to the upper via a center aligning tab removing any chance of rail rotation. This rail is a variant of the 13.5” SMR MK16, currently fielded by USASOC, and one of Geissele's best sellers and best ideas.  At Charlie's, we like the way in which the upper mates to the rail, which also is a crutch to better align the rail and upper receiver.  That is a good thing.  Also new is the steel insert for the QD socket, which adds to the durability of the sling connection.

The upper receiver group includes the upgraded Geissele Reliability Enhanced Bolt Carrier Group.  Each bolt is rigorously inspected, high pressure tested, mag particle inspected.  The Geissele REBCG is Nano-coated for lubricity and superior protection from the elements. The Reliability Enhanced BCG is DLC coated in what Geissele calls "Nanocoating" and is machined from mil-spec 8620 steel, with a properly torqued and staked, chrome lined gas key. The REBCG also features extended upper rails, providing greater stability and dramatically increasing feeding reliability. The REBCG is properly torqued and staked, chrome lined gas key. The Cam Pin is machined from advanced, medical steel known as H13 which is also coated with Nanoweapon for maximum corrosion and wear resistance. The Geissele Reliability Enhanced Bolt Carrier Group also features extended upper rails, providing greater stability and dramatically increasing feeding reliability.

The Geissele Reliability Enhanced Bolt Carrier Group comes with the Geissele Stressproof Bolt. Made from Carpenter 158+, directly developed with Carpenter Steel metallurgists to create a material that is cleaner and has less impurities. This makes our Stressproof bolt stronger and more fatigue resistant. The Geissele Stressproof bolt is also forged, not machined from barstock. This allows us to optimize the grain structure of the steel to yield a bolt capable of 5 times the life of a mil-spec bolt. Each bolt is rigorously inspected, high pressure tested, mag particle inspected and Nanoweapon coated.

Nanoweapon coated, and requires less oil.

The Super Duty upper also includes the  Airborne Charging Handle.  The Mk16 rail is unique to this upper, as it has the dovetail fit to the upper.  This is not a standard Geissele Mk16 rail, nor is the upper a standard Geissele upper.  The two are meant to be used as one system.

The Mod1 Super Duty features the HUXWRX 5.56 QD Flash Hider, which is perfect on its own, or paired with a HUXWRX suppressor.  Additionally, the Mod1 as seemed to standardize now on the heat treated stainless steel inserts / reinforcements for the QD sling attachment points.  This has been quite variable in the past, as Geissele would or would not produce their uppers with the steel fixtures.