Sig Sauer M400 X-Series Semi-Auto Rifle RM400SDI16BP, 5.56 NATO, 16″, Magpul SL-K Stock, Flat Match-Grade Trigger, 30 Rds

SIG SAUER M400 X-Series Semi-Auto Rifle – 5.56 NATO, 16″ Barrel, Magpul SL-K Stock, Flat Match-Grade Trigger, 30-Round

The SIG SAUER M400 X-Series RM400SDI16BP is a premium semi-automatic rifle chambered in 5.56 NATO, designed for shooters seeking enhanced performance, ergonomics, and reliability in a modern AR-platform rifle. Part of SIG SAUER’s upgraded M400 X-Series lineup, this rifle features a 16-inch barrel, lightweight aluminum construction, fully ambidextrous controls, and performance-focused components developed with input from SIG SAUER Academy instructors.

The M400 X-Series features a free-floating M-LOK handguard, Magpul SL-K adjustable stock, and a flat match-grade trigger for improved control and faster follow-up shots. The rifle’s enhanced lower receiver includes ambidextrous controls, providing improved handling for both right- and left-handed shooters.

Built around the proven direct-impingement operating system, the M400 X-Series combines a cold hammer forged barrel, optimized gas system, and precision components to deliver consistent accuracy and dependable operation. The rifle includes a 30-round magazine and is ready for optics and accessory customization.

Specifications

Key Features

• Chambered in 5.56 NATO
• Full-length 16-inch barrel
• M400 X-Series performance upgrades
• Flat match-grade trigger
• Magpul SL-K adjustable stock
• Free-floating M-LOK handguard
• Fully ambidextrous controls
• Cold hammer forged barrel
• Optics-ready Picatinny rail
• AR-15 magazine compatibility
• 30-round magazine capacity
• Designed for training, competition, defense, and general-purpose shooting

The SIG SAUER M400 X-Series 5.56 NATO Rifle combines the familiar AR-15 platform with premium upgrades, offering improved ergonomics, enhanced trigger performance, and SIG SAUER reliability in a versatile 16-inch rifle configuration.