Geissele Automatics MK8 13.5" M-LOK Rail - 6061-T6 Aluminum, Black Anodized for AR-Platform

The Geissele Automatics MK8 13.5" M-LOK rail is a free-float handguard built for shooters who demand modularity without compromise. This AR-15 handguard uses Magpul's M-LOK mounting system across the 3, 6, and 9 o'clock positions, plus the upper 45-degree quadrants, giving you genuine flexibility to configure optics, lights, grips, and other accessories exactly how you shoot. Machined from 6061-T6 aluminum and finished in hard-anodized black, the MK8 strikes the balance between a rigid, accurate platform and practical weight savings that add up over a long day at the range or in the field.

Where the MK8 really sets itself apart is its engineering. Geissele's proprietary 2.25" barrel nut dramatically increases the surface contact area where the rail interfaces with your receiver—the result is a handguard that stays true, shot after shot, and returns to zero reliably after cleaning and reassembly. The lower quadrants are vented at 45-degree angles to shed heat and cut weight, a detail that matters whether you're running fast strings or dealing with sustained fire. At 13.1 oz with hardware, it's light enough to keep your rifle balanced without feeling skeletal.

Installation requires a Geissele barrel nut wrench (sold separately), but once mounted, you've got a handguard that AR builders and shooters trust for precision work. The 13.5" length pairs well with mid-length gas systems and gives you solid real estate for mounting without excessive overhang. Whether you're building a precision rifle, a duty carbine, or something in between, the MK8 M-LOK hands you the tools to make it your own.

Key Features

• M-LOK mounting points at 3, 6, 9 o'clock and upper 45-degree quadrants for modular accessory attachment
• Free-float design for improved accuracy and zero repeatability
• Geissele's 2.25" barrel nut maximizes receiver interface contact for a rock-solid platform
• 6061-T6 aluminum construction with hard-anodized black finish for durability and corrosion resistance
• Lower 45-degree venting reduces weight and improves heat dissipation
• Lightweight at 13.1 oz with hardware—designed for practical, all-day handling
• Includes barrel nut; barrel nut wrench sold separately

Specifications

Frequently Asked Questions

What's included with the MK8 13.5" M-LOK rail?

The handguard ships with the barrel nut. You'll need to purchase a Geissele barrel nut wrench separately for installation.

What AR-15 platforms is this rail compatible with?

The MK8 M-LOK is designed for standard AR-15 platform rifles and uses a Geissele proprietary barrel nut for mounting to your receiver.

How many M-LOK slots does the MK8 have?

M-LOK mounting points are positioned at the 3 o'clock, 6 o'clock, and 9 o'clock positions, plus the upper 45-degree quadrants, giving you multiple options for mounting accessories around the handguard.

How much does the MK8 13.5" weigh?

The MK8 weighs 13.1 oz with all hardware included, making it a lightweight option for builders focused on keeping their rifle balanced and maneuverable.