The M400-SDI X was designed to meet the highest standards of performance and reliability. From the rifle's full suite of ambidextrous controls to its proven mid-length gas system. Features fully Ambi Controls- safety, charging handle, bolt Catch & mag release; 2-Stage Matchlite Duo trigger; free floating M-LOK; mid-length direct impingement operating system and 6 position Magpul SL stock.
| FireArm | yes |
| Weight | 7 lbs |
| Action | Semi-Auto |
| Barrel Description | Threaded |
| Hand | Ambidextrous |
| Trigger | Sig Two-Stage Matchlite Duo |
| Muzzle | Sig Flash Hider-Compensator |
| Sights | None |
| OAL | 33.25' - 36.50" |
| Weight Range | 7 lbs to 7.99 lbs |
| Stock Description | 6 Position Magpul SL |
| Stock Finish Group | Black |
| Barrel Length | 16" |
| Receiver Material | Aluminum |
| Twist | 1:7" |
| Barrel Length Range | 16" to 16.99" |
| Capacity | 30+1 |
| Caliber | 5.56 NATO |
| Safety | Lever |
