Geissele’s Super Modular Rail (SMR) MK4 M-LOK™ represents the brand’s ultra-lightweight take on M-LOK rail systems. The rail ships with integrated M1913 Picatinny rail sections positioned at the 3, 6, and 9 o’clock positions along its length. Extensive venting throughout the design cuts weight significantly while preserving the strength and rigidity of the platform.
The SMR MK4 incorporates Magpul’s M-LOK technology at the 3, 6, and 9 o’clock positions and upper 45 quadrants, delivering genuine modularity that lets you configure your setup around your specific requirements. The 10.5″ rail is machined from 6061-T6 Aluminum and finished with Type 3 Anodized Hardcoat, arriving as a direct fit for AR-15 receivers.
Geissele’s proprietary 2.25″ long barrel nut sets this rail apart by expanding the contact surface where the rail meets the receiver, ensuring the free float rail remains straight and true along its full length. This design choice improves accuracy and zero repeatability during maintenance cycles that involve disassembly and reassembly. The DDC finish offers a combat-tested color that integrates cleanly with modern tactical platforms.
