SIG SAUER M400 SDI 10 Inch M-LOK Free-Float Handguard

The SIG SAUER M400 SDI 10" M-LOK Handguard is a genuine factory replacement designed specifically for the SIG M400 SDI X and TREAD platforms, while maintaining full compatibility with standard AR-15 mil-spec builds.

Machined from lightweight aluminum and finished in durable black anodizing, this free-float handguard improves accuracy by eliminating barrel contact during supported or rested shooting. Integrated M-LOK slots along the sides and bottom allow easy mounting of lights, grips, and accessories, while the M1913 Picatinny top rail supports optics and iron sights with a continuous, rigid mounting surface.

Strategic lightening cuts reduce overall weight without sacrificing strength, keeping the rifle balanced and maneuverable. Whether you’re restoring a factory SIG rifle or upgrading a custom AR-15 build, this handguard delivers factory-correct fit, clean aesthetics, and proven performance.

This kit includes the barrel nut, clamps, and installation hardware, making it a complete drop-in solution for compatible rifles.

Key Features & Benefits

• Genuine SIG SAUER factory M400 SDI X handguard

• Free-float design improves accuracy and consistency

• M-LOK slots on sides and bottom for modular accessories

• M1913 Picatinny top rail for optics and sights

• Lightweight aluminum construction with lightening cuts

• Durable black anodized finish

• Complete kit includes barrel nut, clamps, and screws

• Compatible with standard AR-15 mil-spec platforms

Included in the Box

• SIG SAUER M400 SDI 10" Handguard

• Barrel Nut

• Barrel Clamps

• (2) Mounting Screws

• Installation Hardware