The Geissele Super Modular Rail MK4 Federal (brand part number 05-430S) is a 10-inch, drop-in M-LOK handguard machined from aluminum and finished in Desert Dirt Color for AR-platform rifles. It features integrated M1913 picatinny rail sections at the 3, 6, and 9 o’clock positions at the front of the rail, and the bottom picatinny section is elongated on this version to more comfortably accommodate lights, lasers, or grips. Maximum venting cuts weight and improves heat dissipation while keeping the platform strong and rigid, and M-LOK slots at the 3, 6, and 9 o’clock positions plus the upper 45-degree quadrants give shooters full freedom to mount accessories exactly where they need them.

Key Specifications

• Length is 10 inches, a compact handguard length suited to shorter-barreled carbine builds.
• Attachment style is drop-in, mounting to the upper receiver without a separate barrel nut installation step.
• Mounting system is M-LOK, at the 3, 6, and 9 o’clock positions plus the upper 45-degree quadrants.
• Integrated M1913 picatinny rail sections sit at the 3, 6, and 9 o’clock positions at the front of the rail.
• Bottom picatinny section is elongated on this version for easier mounting of lights, lasers, or grips.
• Finish is Desert Dirt Color (DDC) over an aluminum body.
• Venting is maximized for heat dissipation and reduced overall weight.

Frequently Asked Questions

What mounting system does this handguard use? It uses M-LOK slots at the 3, 6, and 9 o’clock positions and the upper 45-degree quadrants.

Is it drop-in or does it require a proprietary barrel nut? It is a drop-in design that mounts to the upper receiver.

What length is this handguard? It is 10 inches long.

Buy the Geissele Super Modular Rail MK4 Federal

Free-float your build with a rigid, low-weight Geissele handguard. Shop more Geissele Automatics rails in our AR handguards selection, and this handguard ships fast from our Lubbock, Texas gun shop.