- Ambidextrous Bolt Catch and Release
- Compensator/Flash Hider
- Dual Clamp Handguard Locking System for Reduced Deflection
- Low-Profile Gas Block with Mid-Length Gas System
- Sig 2-Stage Matchlite Duo Trigger
- Magpul SL Stock
The SIG SAUER M400 SDI X-Series 5.56mm NATO Semi-Automatic Rifle has been developed with the input from the professional instructors at SIG SAUER Academy. Building upon their decades of experience and countless hours of instruction, they have developed the M400-SDI X to meet the highest standards of performance and reliability.
With fully ambidextrous controls including a bolt catch/and release unique to the M400-SDI lower-receiver, the M400-SDI X delivers advanced performance for both left and right-handed shooters and makes transitional shooting easier than ever. The free-floating handguard utilizes a new steel lockup design that significantly reduces handguard deflection by providing maximum rigidity and allows for accessories to be attached on all four sides with no effect on accuracy.
The 2-Stage Matchlite Duo trigger provides an out-of-the-box crisp 4.5 – 6.5lb pull weight with a flat blade design for a precision feel. The M400-SDI X utilizes the highest quality performance coatings to ensure maximum durability and reliability.








