Geissele Super Modular MK4 M-LOK AR-15 Handguard

The Geissele Super Modular MK4 Rail is an ultra-light, precision-machined free float handguard built specifically for the AR-15 platform. Designed for rigidity, repeatable zero retention, and modular flexibility, the MK4 delivers professional-grade performance without excess weight.

Machined from 7000 Series aluminum and finished in Type III hardcoat anodizing, this rail is built to handle serious use while maintaining a refined, streamlined profile.

Precision Free Float Design

Proprietary Barrel Nut System
The included barrel nut increases surface contact between the rail and upper receiver, enhancing rigidity and improving accuracy and repeatability if the handguard is removed for maintenance.

True Free Float Platform
Eliminates pressure on the barrel, allowing consistent harmonics and improved accuracy potential.

Advanced Mounting System

M-LOK on Five Surfaces
Accessory slots run along five sides of the rail, allowing flexible placement for lights, grips, bipods, and mission-specific equipment while promoting airflow for cooling.

Full-Length M1913 Picatinny Top Rail
Continuous top rail supports optics, backup irons, and night vision devices.

Integrated Front Rail Sections
M1913 sections at the 3, 6, and 9 o’clock positions near the muzzle allow solid mounting of weapon lights and bipods.

Lightweight Strength

7000 Series Aluminum Construction
Engineered for durability while keeping weight minimal.

Type III Hardcoat Anodized Finish
Available in Black and Desert Dirt Color (DDC) for corrosion resistance and long-term durability.

9.3" Model Weight
11.0 oz (weight varies slightly by length).

Available Configurations

Black
9.3"
10"
13.5"
15"

Desert Dirt Color (DDC)
9.3"
13.5"
15"

Ideal For

Duty rifle builds
Competition AR setups
Precision-focused builds
Modular tactical platforms