The SIG SAUER M400 SDI delivers proven direct impingement reliability in a versatile 5.56 NATO platform built for serious applications. This 16-inch barreled rifle combines military-grade construction with civilian accessibility, offering consistent performance across training, competition, and defensive scenarios.
What Makes This Different
The M400 SDI features SIG's refined direct impingement gas system with enhanced bolt carrier group tolerances for improved cycling reliability. Unlike basic AR-15 platforms, this rifle includes a free-floating M-LOK handguard that maintains barrel harmonics while providing multiple attachment points. The green anodized finish offers enhanced corrosion resistance compared to standard mil-spec coatings.Key Features
- 16-inch chrome-lined barrel with 1:7 twist rate for optimal bullet stabilization
- Free-floating M-LOK handguard with full-length Picatinny top rail
- Enhanced trigger group with crisp break and positive reset
- Six-position telescoping stock with multiple length-of-pull adjustments
- Ambidextrous safety selector and magazine release controls
- Green anodized aluminum receivers with Type III hard coat finish
- Standard AR-15 magazine compatibility including 30-round capacity
Technical Specs
- Caliber: 5.56 NATO/.223 Remington
- Barrel Length: 16 inches, chrome-lined with 1:7 twist
- Overall Length: 32.5-35.5 inches (stock collapsed/extended)
- Weight: 6.5 pounds unloaded
- Receiver Material: 7075-T6 aluminum with green anodized finish
- Handguard: Free-floating M-LOK with 15-inch length
- Trigger: Single-stage with 6-7 pound pull weight
- Magazine Capacity: 30 rounds (where legally permitted)
- Country of Origin: United States
