SIG SAUER M400 Forge 5.56 NATO Rifle – 16 Inch, Moss Green

Description

SIG SAUER M400 Forge 5.56 NATO Rifle in Moss Green

The SIG SAUER M400 Forge combines a forged-receiver AR-platform rifle with upgraded factory components that normally require separate selection and installation. This exact Moss Green configuration, manufacturer part number RM400-556N-16B-FORGE-MSGRN and UPC 798681744206, is chambered in 5.56 NATO and arrives with a 16-inch cold-hammer-forged barrel, a ROMEO-MSR Gen II red-dot sight, and one 30-round polymer magazine.

Its mid-length direct-impingement operating system is paired with a 1:7-inch twist barrel. That fast twist rate supports a broad selection of common 5.56 NATO projectile weights, while the cold-hammer-forged steel construction is intended for durability through regular range, training, and defensive use. The muzzle is threaded 1/2×28 with a 90-degree shoulder and fitted with an A2 birdcage flash hider.

Factory-Installed ROMEO-MSR Gen II

This rifle includes SIG SAUER’s ROMEO-MSR Gen II optic with a 2 MOA red dot. The compact aiming point supports fast acquisition at close range while remaining precise enough for deliberate shooting at distance. Because the optic is included from the factory, the rifle is ready for zeroing without requiring the buyer to select a separate sight before the first range session. As with any optic-equipped rifle, confirm mounting security and establish a live-fire zero with the intended ammunition before relying on it.

TriggerTech Two-Stage Duty Trigger

A TriggerTech 3.5-pound two-stage flat-blade duty trigger is another defining M400 Forge feature. The two-stage design provides a deliberate initial take-up followed by a predictable break, giving the shooter a clear sense of trigger movement without turning the rifle into a specialized competition-only setup. The flat trigger face provides a consistent contact surface across different finger positions.

Modern Controls and Furniture

The free-floating alloy handguard uses M-LOK attachment slots and a full-length Picatinny top rail, allowing lights, sling hardware, support grips, and other compatible equipment to be positioned for the individual shooter. An ambidextrous charging handle improves access from either side. The reduced-angle pistol grip and six-position Magpul SL-K stock support compact handling and adjustable length of pull for different body types, clothing layers, and shooting positions.

This version is finished in Moss Green Cerakote across the receiver and matching M-LOK handguard. The coating gives the rifle a distinctive subdued appearance while the black barrel, controls, magazine, stock, grip, and optic provide practical contrast.

Size and Handling

At 6.8 pounds, the M400 Forge remains manageable for extended range sessions while carrying an optic and full-length handguard from the factory. The stock adjusts from a collapsed overall length of 32.25 inches to a maximum overall length of 35.5 inches, allowing the rifle to fit different shooters and working positions. The mid-length gas system, adjustable stock, and free-floating handguard create a versatile general-purpose configuration suitable for training, property defense, and recreational shooting without requiring immediate furniture, trigger, or sight upgrades.

Key Specifications

• Manufacturer: SIG SAUER
• Model: M400 Forge
• MPN: RM400-556N-16B-FORGE-MSGRN
• UPC: 798681744206
• Caliber: 5.56 NATO
• Action: Semi-automatic, mid-length direct impingement
• Barrel: 16-inch cold-hammer-forged steel
• Twist rate: 1:7 inches
• Muzzle threads: 1/2×28, 90-degree shoulder
• Muzzle device: A2 birdcage flash hider
• Optic: ROMEO-MSR Gen II with 2 MOA red dot
• Trigger: TriggerTech 3.5-pound two-stage flat blade
• Handguard: Free-floating M-LOK alloy with full-length Picatinny rail
• Stock: Six-position Magpul SL-K
• Safety: Ambidextrous
• Capacity: 30+1
• Magazine: One 30-round polymer magazine
• Finish: Moss Green Cerakote
• Overall length: 35.5 inches
• Collapsed length: 32.25 inches
• Weight: 6.8 pounds

Purchase and Responsible Use

This rifle must be transferred through a licensed dealer in accordance with federal, state, and local law. Magazine-capacity and firearm-feature restrictions vary by jurisdiction, so confirm legal eligibility before ordering. Read the owner’s manual before use, keep the muzzle pointed in a safe direction, keep the finger outside the trigger guard until ready to fire, and use appropriate eye and hearing protection. Inspect and clean the rifle before its first range session, then verify reliable operation with the intended ammunition and magazine.