Super Modular Rails

Super Modular Rail MK4 M-LOK

Super Modular Rail MK4 M-LOK

Super Modular Rail MK4 M-LOK

MK4 Height:


Available Lengths: 

 7"  •   9.5"  •  13"  •  15"

MK4 ID*:




Installed Weight
(w/ Hardware):

7” MK4 Rail - 9.7oz
9.5” MK4 Rail - 11.0oz
13”  MK4 Rail - 14.1oz
15” MK4 Rail - 15.4oz 

ID* - Inner Diameter
OD* - Outer Diameter
DAQ* - Distance Across Quadrants

Available in Black and DDC

.750" Low Profile Stainless Steel Geissele Super Gas Block Included

Click Here to review our DDC (Desert Dirt Color) disclaimer before purchasing.

NOTE: Our rails are designed to work with Mil-Spec M4 upper receivers. The compatibility with billet receiver sets is unknown.


Item Number:



In stock

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Super Modular Rail MK4 M-LOK

Full Description

The Super Modular Rail (SMR) MK4 M-LOK™ is Geissele’s ultra-lightweight M-LOK option. These rails are purpose-built and feature integrated M1913 picatinny rail sections at the fore of the rail in the 3, 6 and 9 o’clock positions. Maximum venting for heat dissipation also dramatically reduces the rail's overall weight, while maintaining its same strong and rigid platform. Utilizing Magpul's M-LOK technology at the 3, 6, and 9 o'clock positions, as well as the upper 45 quadrants. The SMR MK4 is both versatile and modular, allowing the user to tailor their platform to his or her unique needs.

The SMR MK4 also features Geissele's proprietary 2.25" long barrel nut. This increases the surface contact where the rail interfaces with the receiver and creates a platform that can be trusted to be straight and true the entire length of the free float rail. This increases accuracy and zero repeatability during disassembly and reassembly when performing maintenance.

Bundled with a low-profile Geissele Super Gas Block, a $59 value, the SMR MK4 is not only feature packed, but it is also value packed.

Super Modular Rail MK4 M-LOK

Reviews (2)

overall rating 5.0

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Best rails I've owned - Joelski

I have Mk 4's on two rifles and can't say enough good about them. The 1913 at the end allows ideal placement of my bipod and the M-Lok at 10:30 and 1:30 allow tight-in mounting of your weapon mounted lights. These rails have what I need, where I need it, and nothing I don't need everywhere else. Looking forward to adding a Mk 13 to my next rifle, Thanks for the dependable gear!

November 16th, 2017

MK4 outstanding - Brian

I recently purchased the MK4 9" rail, the quality is outstanding, and the customer service is even better. I'll be buying more. Thanks

June 20th, 2017
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