Geissele Automatics Mk16 Sm Rail 13.5'' M-Lok For Ar-15 Blk

The Geissele Automatics Mk16 Sm Rail 13.5'' M-Lok is a purpose-built handguard designed for AR-15 shooters who demand reliability and modularity without compromise. Built to military standards—it's the rail adopted by USASOC for the URG-I (Upper Receiver Group Improved) program—this 13.5-inch platform gives you a versatile mounting surface for optics, lights, lasers, and other tactical accessories. Whether you're running a competition rifle, a duty gun, or a serious hunting setup, the Mk16 delivers the rigidity and control that separate a fine rifle from a tool you can trust.

Installation is straightforward thanks to Geissele's proven barrel nut design, which features anti-rotation tabs and set-screws to prevent the rail from shifting under recoil or rough handling. The top runs a full-length M1913 picatinny rail for conventional scope mounts and accessories, while M-LOK slots on all four sides give you infinite positioning options for vertical grips, sling mounts, pressure switches, and other gear. No need to guess where to attach something—you'll find a compatible slot or rail segment wherever you need it.

Precision-machined from 6061-T6 aluminum and finished in Type 3 hardcoat anodize, the Mk16 balances weight and durability. At 13.4 ounces (or 14.9 with the barrel nut), it won't burden your rifle or tire your arms on a long day afield or at the range. The 1.59-inch outer diameter keeps the profile sleek while maintaining the structural rigidity shooters expect from a Geissele product. If you're running a shorter setup, a 9.3-inch variant is available separately.

This is a no-frills, no-marketing rail—just a piece of gear designed for people who know what they're doing and expect their equipment to perform.

Key Features

• Adopted by USASOC for URG-I program—military-tested design
• Full-length M1913 picatinny rail on top; M-LOK slots on all quadrants for unlimited accessory mounting
• Anti-rotation tabs and set-screws lock the rail to your upper receiver—zero movement under recoil
• Lightweight 6061-T6 aluminum construction with Type 3 hardcoat anodize finish
• Proven Geissele barrel nut design for easy, reliable installation
• 13.5-inch length balances sight radius and handling

Specifications

Frequently Asked Questions

Will the Mk16 Sm Rail fit my AR-15?

Yes—the Geissele Mk16 13.5'' is designed for AR-15 upper receivers. It mounts using a standard barrel nut and is compatible with most AR-15 builds. If you're unsure about your specific upper, contact us or verify your upper's compatibility before ordering.

What's the difference between the 13.5'' and the 9.3'' version?

The 13.5-inch Mk16 gives you more rail space and sight radius, making it ideal for longer-range or precision setups. The 9.3-inch variant is available separately for shooters running shorter platforms or wanting a more compact profile. Both share the same construction quality and feature set.

Can I mount accessories to both the picatinny and M-LOK slots?

Yes. The top of the rail features a continuous M1913 picatinny section, and M-LOK slots run on all four sides. You can mix and match—picatinny for standard rail-mounted accessories and M-LOK for lightweight or modular components like grips, sling mounts, and light switches.

How much does the barrel nut add to the weight?

The barrel nut adds approximately 1.5 ounces to the rail's 13.4-ounce weight, bringing the total installed weight to 14.9 ounces.