The Geissele Super Modular Rail MK2 (SMR) was designed to be a cost effective option to our SMR MK1. Our SMR MK2 is designed to fit the M4 Carbine and all mil-spec AR-15 variants. The SMR MK2 was designed to do a good job in meeting the ten design specifications for a good M4 weapon rail while being a cost effective alternative to the SMR MK1.
Instead of four sharp and jagged M1913 rails spaced at 90 degree intervals, the SMR MK2 only has a M1913 rail at the 12 o’clock position while at 9, 3 and 6 o’clock is a flat mounting surface for accessory rails. The flat mounting surfaces feel much better in the hand than the sharp edges of a M1913 rail.
2. SET-UP IS MODULAR AND FLEXIBLE
Accessory rails in the standard M1913 (Picatinny) configuration are provided with each SMR MK2 so accessories can be mounted where the shooter desires. Two short and one long accessory rail are provided with each SMR kit. There is also a QD mount at the receiver end that accepts an industry standard QD swivel.
3. FREE FLOATING
The weapon barrel is completely free floating when an SMR MK2 is mounted. No force is put into the barrel from slings or bipods that could effect point of aim.
The SMR MK2 is machined from a semi-billet extrusion made from aircraft grade aluminum. A semi billet extrusion is designed with extensive machining stock for 3D features that are machined directly into the rail so that the rail is one integral piece.
Current infantry doctrine makes extensive use of accessories that require attachment to a weapon rail. Flashlights, visible and infrared lasers, night vision and thermal sights all require a rigid weapon rail so that zero is not changed when a bipod or sling is used to support the weapon from the rail. The SMR MK2 is a rigid interface for weapon accessories due to its precisely machined proprietary barrel nut and secure rail interface and clamping arrangement.
Use of aircraft grade aluminum and high strength steels in the SMR MK2 give the entire assembly a good strength and performance to weight ratio. The MK2 has good balance with the center of gravity of the rail biased toward the receiver for good weapon handling characteristics.
7. ACCESSORY RAILS EASY TO INSTALL
Accessory rails are fastened to steel slide nuts instead of imbedded steel inserts like the MK1. The slide nuts are fully captured in channels configured in the rail ID. Slide nuts are much more soldier proof than inserts as a cross threaded screw can easily be repaired with the replacement of a slide nut. It takes literally seconds to install or remove an accessory rail without standing on your head to deal with non-captured plate nuts.
8. ACCESSORY RAILS ARE STRONG
The SMR MK2 accessory rails have machined in shear lugs that are a close fit into the cooling slots that are machined into the rail. Any force imparted into the accessory rail is transferred directly into the rail and bypasses the mounting screws. This means that the mounting screws only need to hold the accessory rail on and not resist side loads that can make the screws loosen over time.
9. RAIL ASSEMBLY IS EASY TO INSTALL
Each SMR MK2 comes with a precisely machined, 2-1/4” long alloy steel barrel nut (same as the MK1) and a combination wrench that will remove the stock barrel nut and install the Geissele one. The Geissele barrel nut needs no indexing to the gas tube so installation is a snap with just a torque value used for tightening. The rail is then slid onto the barrel nut and the precise barrel nut to rail fit precisely aligns the rail to the barrel. After indexing to the receiver rail two mounting bolts are tightened and the rail is secure.
10. RAIL IS EASY TO REMOVE
Just by loosening two screws and one of the indexing screws the Geissele SMR MK2 can be slid off the barrel nut for cleaning or gas system maintenance. Even a different rail with a different accessory configuration can be mounted. As quick as it is removed the SMR MK2 is can be re-installed with the precise barrel nut to rail fit maintaining sight and accessory zero.
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