The 11.5” complete upper in 5.56mm features an Black upper receiver mated to a unique Mk16 MLOK rail with 11.5”  Black Oxide coated, Cold Hammer Forged Geissele, Chrome Lined 1-7 twist barrel, with nano-coated Surefire closed tine Surefire SOCOM flash hider and a Geissele low profile bomb-proof factory installed gas block.

This is a Geissele Factory upper receiver group with Nano-coated Surefire flash hider and steel reinforce QD grommets

Geissele barrels were a new line for Geissele in 2020, and further refined in 2021.  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.

This Geissele factory constructed Super Duty Upper Receiver Group features the Geissele Reliability Enhanced Bolt Carrier Group.

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.

Note:  Geissele has, over the years, used a number of specifications for their Super Duty Upper Receivers.  This is a new old stock model, which has the Surefire flash hider, and upgraded QD sling steel reinforced grommets.  The Surefire Closed-Tine flash hider is preferred by many users over the Geissele proprietary mount that succeeded this model in 2023, before being replaced in 2024 with the HUXWRX model.  If you plan to use suppressed, this flash hider will work well with most all Surefire suppressors made in the last decade. The nanocoating provides extra protection and has a deep black color.

The Super Duty Complete Upper from Geissele Automatics offers unmatched performance, accuracy and reliability.