Midwest Industries SIG MPX M-LOK Handguard 8"

Midwest Industries makes the most-installed aftermarket handguard on the SIG MPX. Constructed from 6061 aluminum with a hard-coat anodized matte black finish, it replaces the original SIG KeyMod handguard (Gen 1) or the short factory M-LOK shroud (MPX K) with a full-length 8-inch aluminum tube that runs continuous M-LOK slots and half-slots along the sides and bottom plus a full-length 1913 Picatinny top rail. The handguard is a drop-in installation that uses the OEM mounting hardware and the heat-treated 4140 retaining clip with black phosphate finish ships in the box.

Eight inches is the sweet spot for most MPX builds. It clears a typical 4.5-inch K barrel suppressor mount or a 6.5-inch ILWT barrel without binding, and it gives enough rail real estate to mount a Surefire M340-class scout light at a natural support-hand position with a vertical grip or hand-stop forward of it. Owners running shorter barrels (the 4.5-inch K with no suppressor) typically prefer the 6.5-inch length; owners running 14-inch SBR or 16-inch carbines step up to the 14-inch.

The MI handguard is the volume pick because it works, costs less than the carbon-fiber competition, and Midwest Industries support is dependable. For shooters chasing absolute weight savings or thermal management for hard suppressed use, the Lancer carbon-fiber MPX handguard is the upgrade tier above this.