The 10.3” complete upper in 5.56mm features an DDC upper receiver mated to a unique Mk16 M-LOK rail with 10.3”  Black Oxide coated, Cold Hammer Forged Geissele, Chrome Lined 1-7 twist barrel, with nano-coated HUXWRX flash hider and a Geissele low profile bomb-proof factory installed gas block.

This is a Geissele Factory upper now with HUXWRX flash hider

Geissele barrels have come a long way.  The barrels are precision machined and cold hammer forged. The carbine length gas system is perfect for the 10.3" 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 9.3” 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 bestsellers 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.

In addition to the great rail and amazing good looks of the DDC matched receiver set, Geissele also features their top shelf BCG on this Close Quarter Battle Receiver, 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 bar stock. 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.

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 on flash hider:  Geissele has, over the years, used a number of specifications for their Super Duty Upper Receivers. This is a new model, which has the HUXWRX flash hider.  If you plan to use suppressed, this flash hider will work well with the next generation HUXWRX suppressors. The nanocoating provides extra protection and has a deep black color.

Note on QD sling sockets:  This model comes with the steel reinforced grommets.