Sig Sauer M400 SDI 5.56 NATO 11.5" Barrel 30rd Black Rifle

The Sig Sauer M400 SDI delivers proven AR-15 platform reliability in a compact configuration optimized for close-quarters applications. This 5.56 NATO chambered rifle combines an 11.5-inch chrome moly steel barrel with M-LOK compatibility for versatile accessory mounting.

What Makes This Different

The M400 SDI features Sig Sauer's direct impingement gas system engineered for consistent cycling with both 5.56 NATO and .223 Remington ammunition. The mid-length gas system reduces felt recoil and extends component life compared to carbine-length alternatives. Chrome moly steel barrel construction provides enhanced accuracy and corrosion resistance over standard carbon steel options.

Key Features

• 11.5-inch chrome moly steel barrel with 1:7 twist rate for stabilizing heavy projectiles
• M-LOK handguard system accepts accessories without additional rail sections
• Direct impingement gas system with mid-length gas tube configuration
• 30-round magazine capacity with STANAG compatibility
• Anodized aluminum upper and lower receivers resist corrosion
• Polymer pistol grip provides secure handling in wet conditions
• Standard AR-15 trigger group accepts aftermarket upgrades

The compact 11.5-inch barrel length maintains maneuverability in confined spaces while delivering effective range out to 300 yards. Law enforcement and competitive shooters appreciate the balance between portability and ballistic performance. The chrome moly steel barrel handles sustained firing schedules without accuracy degradation, making it suitable for training applications and duty use.

Technical Specs

• Caliber: 5.56 NATO/.223 Remington
• Barrel Length: 11.5 inches
• Barrel Material: Chrome moly steel
• Twist Rate: 1:7 inches
• Gas System: Mid-length direct impingement
• Handguard: M-LOK compatible aluminum
• Finish: Type III hard coat anodized black
• Magazine Capacity: 30 rounds
• Overall Length: Approximately 32 inches (stock extended)
• Weight: Approximately 6.5 pounds (unloaded)

The M400 SDI represents Sig Sauer's commitment to manufacturing AR-15 platform rifles that meet military specifications while remaining accessible to civilian shooters. The combination of proven components and quality control standards ensures reliable function across diverse operating conditions.