Geissele Automatics AR-15 15" Super Modular Rail MK4 M-LOK

The Geissele Automatics AR-15 15" Super Modular Rail (SMR) MK4 M-LOK combines maximum rigidity, modular flexibility, and lightweight performance for your custom AR-15 build. Engineered to perform in demanding conditions, the MK4 features full-length M-LOK slots at the 3, 6, and 9 o'clock positions, paired with short integrated Picatinny rail sections at the muzzle end to seamlessly mount lights, lasers, and vertical grips without adding unnecessary bulk.

Constructed with precision manufacturing, the MK4 utilizes a robust barrel nut mounting system to ensure minimum flex and optimal accuracy under hard use.

Key Features & Specifications:

• Length: 15 inches
• Mounting System: M-LOK modular design with integrated forward Picatinny quad-rail sections
• Overall Weight: 15.1 oz. (including mounting hardware)
• Height: 2.4"
• Inner Diameter: 1.35"
• Outer Diameter: 2.11"
• Included: Barrel Nut (Note: Barrel Nut Wrench sold separately)