The Sig Sauer M400 Forge With Romeo-MSR Gen II delivers a compact AR-style pistol that is ready to run the moment it leaves the box. Built around an 11.5" cold hammer forged barrel with an A2 birdcage flash hider and a 10" free-floating M-LOK handguard, this 5.56 NATO platform balances smooth cycling, durability, and practical accuracy. The included Romeo-MSR Gen II 2 MOA red dot, TriggerTech 3.5-pound two-stage flat blade trigger, and ambidextrous charging handle round out a clean, modern configuration.

This M400 Forge configuration is well suited for range work, training, and duty use where a shorter overall length and stable Magpul BSL arm brace are beneficial. The full-length Picatinny rail and M-LOK handguard make it easy to add lights or other accessories, while the lightweight alloy receiver keeps handling quick and predictable. For shooters who appreciate dependable performance and thoughtful details, this pistol reflects Sig Sauer’s reputation for careful engineering and consistent quality.

• Manufacturer: Sig Sauer
• Model: M400 Forge With Romeo-MSR Gen II
• Caliber: 5.56 NATO
• Action: Semi-Auto
• Barrel Length: 11.5"
• Number of Magazines: 1
• Capacity: 30
• Optic Footprint: Romeo-MSR Gen II 2 MOA Red Dot
• Unique Features: TriggerTech 3.5-Pound Two-Stage Flat Blade Trigger, Magpul BSL Arm Brace, 10" M-LOK Handguard, Ambidextrous Charging Handle
• Threaded Barrel: Yes
• What's In The Box: Pistol, Romeo-MSR Gen II Red Dot, 30-Round Magazine
• Weight: 6.2 Lb
• Length: 27.8"–29.8"
• Width: 2.7"