Sig Sauer RM400SDI16BMSGRN | M400 SDI | 5.56 | 16 in

The Sig Sauer M400 SDI is a 5.56 NATO semi-automatic modern sporting rifle finished in Moss Green Cerakote and built around a mid-length direct impingement gas system. It features fully ambidextrous controls, a free-floating M-LOK handguard, a 16 inch cold hammer-forged barrel and a SIG 2-stage Matchlite Duo trigger for consistent shot control. This configuration suits range training and competitive shooting such as three-gun or practical rifle matches. A Vortex Strike Eagle 1-6×24 or similar optic under $1000 pairs well for fast target acquisition and versatile engagement distances.

Product Specifications

• The UPC is 798681701216.
• The manufacturer is Sig Sauer.
• The model is M400 SDI.
• The cartridge designation is .223 REM/5.56 NATO.
• The barrel length is 16 inches.
• The barrel is constructed as Cold Hammer Forged Steel.
• The twist rate is 1:7.
• The action type is Semi-Auto.
• The operating system is Mid-Length Direct Impingement.
• The muzzle device is a SIG Flash Hider-Compensator.
• The forend is a Free-floating M-LOK handguard with Moss Green Cerakote.
• The stock is a 6-Position Magpul MOE-SL Black.
• The trigger is a SIG 2-Stage Matchlite Duo (flat).
• The package includes (1) 30rd Polymer Mag.
• The magazine capacity is 30 rounds.

The M400 SDI combines proven AR ergonomics with thoughtful controls and a durable finish, delivering a balanced rifle for serious range work and competition. Its ambidextrous features and match-grade trigger make it straightforward to run under stress, while the cold hammer-forged barrel and threaded muzzle provide a solid foundation for aftermarket optics and accessories. If you value a serviceable, well-specified platform in a subdued Moss Green finish, this rifle presents a sensible choice for extended use and customization.

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