The M400 SDI XSeries is built with an aluminum M-LOK handguard, allowing for easy attachment of accessories while maintaining a lightweight design. The Sig 2-Stage Matchlite Duo trigger ensures a crisp, predictable break, improving precision for tactical, defensive, and sport shooting applications. This rifle is optics-ready, featuring a flat-top upper receiver for customizable sighting options. The threaded barrel (1/2x28) allows for suppressor or muzzle device attachment, while the Sig Flash Hider Compensator helps reduce recoil and muzzle rise. The ambidextrous safety makes it versatile for both right- and left-handed shooters.