SIG Sauer M400 Tread 5.56 NATO 16" Rifle 10-Round Black

The SIG Sauer M400 Tread delivers mil-spec reliability in a civilian-legal configuration designed for precision shooting and tactical applications. This direct impingement AR-15 platform combines proven SIG engineering with enhanced ergonomics for superior handling characteristics.

What Makes This Different

Built on SIG's enhanced lower receiver with ambidextrous controls, the M400 Tread features a free-floating M-LOK handguard that maintains barrel harmonics for consistent accuracy. The 16-inch barrel utilizes a 1:7 twist rate optimized for both 55-grain and heavier projectiles, while the SIG Tread stock system provides multiple length-of-pull adjustments. Unlike standard mil-spec triggers, this rifle includes SIG's single-stage trigger with a crisp 6-pound break.

Key Features

• 16-inch chrome-lined barrel with 1:7 twist rate for versatile ammunition compatibility
• Free-floating 13.5-inch M-LOK handguard with full-length top rail
• Ambidextrous safety selector and magazine release for enhanced manipulation
• SIG Tread 6-position collapsible stock with integrated storage compartment
• Single-stage trigger assembly with 6-pound pull weight
• 10-round Magpul PMAG included for restricted state compliance
• Flat-top upper receiver with full-length Picatinny rail system

Field testing demonstrates sub-2 MOA accuracy with quality ammunition, making this platform suitable for competitive shooting, patrol duties, and precision applications. The direct impingement gas system cycles reliably with standard 5.56 NATO and .223 Remington loads, while the chrome-lined bore extends service life in high-volume shooting scenarios. Weather-resistant finishes protect against corrosion in demanding environments.

Technical Specs

• Caliber: 5.56 NATO/.223 Remington
• Barrel Length: 16 inches with 1:7 twist rate
• Overall Length: 32.5-35.5 inches (stock extended)
• Weight: 6.5 pounds unloaded
• Magazine Capacity: 10 rounds (Magpul PMAG)
• Handguard: 13.5-inch free-floating M-LOK
• Stock: SIG Tread 6-position collapsible
• Finish: Black anodized aluminum/phosphate steel
• Country of Origin: United States

The M400 Tread represents SIG's commitment to manufacturing excellence with enhanced features that exceed standard AR-15 specifications. Professional-grade components and quality control standards ensure reliable performance when accuracy matters most.