Sig Sauer RM400-SDI-16B-R5FX M400 SDI XSeries 5.56 NATO 16" 1:7" Bbl Black Rifle w/ Romeo5 Gen II Red Dot Sight, Foxtrot Rail Mtd Light & (1) 30rd MagThe Sig Sauer M400 SDI XSeries RM400-SDI-16B-R5FX is a 5.56 NATO rifle with a 16-inch barrel and a 1:7 twist rate, making it well-suited for stabilizing heavier bullets. Finished in black, this rifle comes as a complete package that includes a Romeo5 Gen II red dot sight for fast target acquisition, and a Foxtrot rail-mounted tactical light for low-light use. It features a free-floating M-LOK handguard, enhancing accuracy and allowing for accessory customization. The Sig Sauer RM400-SDI-16B-R5FX rifle also includes Sig's XSeries ergonomic upgrades for better handling and control, and it ships with one 30-round magazine. The full-length Picatinny rail on top provides additional flexibility for optics and attachments. Features Include: ROMEO5 GENII Red Dot, FOXTROT-MSR Full Size Light and Vertical ForegripFully Ambidextrous ControlsFree-Floating M-LOK Forend(3) M-LOK Rail Covers Included (3) M-LOK Rail Covers IncludedSIG 2-Stage Matchlite Duo Trigger16” Chrome/Moly Steel Barrel with 1:7 Twist Rate6-Position Magpul MOE-SL StockLow Profile Gas Block with Mid-Length Operating System. yellow-box p {font-size:16px}.special-tab {color: #FFFFFF}The Sig Sauer M400 SDI XSeries was developed in collaboration with the expert instructors at SIG SAUER Academy, drawing on decades of experience and hands-on training. Engineered to exceed the highest standards of performance and reliability, this rifle is built for both professional and enthusiast shooters. Featuring fully ambidextrous controls, including a unique M400-SDI lower receiver with an ambidextrous bolt catch and release, the Sig Sauer M400 SDI XSeries Rifle ensures seamless operation for both left- and right-handed shooters. This design also enhances transitional shooting, making it more intuitive and efficient in dynamic environments. The free-floating handguard incorporates a steel lockup system that drastically reduces deflection, providing maximum rigidity and ensuring that mounted accessories on all four sides have zero impact on accuracy. At the heart of the rifle is the 2-Stage Matchlite Duo trigger, delivering a crisp, precision feel with a 4.5 - 6.5 lb pull weight and a flat-blade design for enhanced control. To maximize durability and reliability, the M400-SDI X is coated with high-performance finishes, ensuring long-lasting performance in the harshest conditions. Features of the Sig Sauer M400 SDI XSeries: Available with a Moss Green Cerakote, FDE Cerakote, or Black Anodized FinishAmbidextrous Bolt Catch and ReleaseCompensator/Flash HiderDual Clamp Handguard Locking System for Reduced DeflectionLow-Profile Gas Block with Mid-Length Gas SystemSIG 2-Stage Matchlite Duo TriggerMagpul SL Stock Sig Sauer M400 SDI XSeries 5.56 NATO 16" 1:7" Bbl Black Rifle w/ Romeo5 Gen II Red Dot Sight, Foxtrot Rail Mtd Light & (1) 30rd Mag RM400-SDI-16B-R5FX