SIG SAUER M400 ROSE 5.56 NATO Rifle with ROMEO5 Gen II

Description

SIG SAUER M400 ROSE 5.56 NATO Rifle

The SIG SAUER M400 ROSE combines the proven M400 direct-impingement platform with factory-selected controls, furniture and optics developed for the ROSE community. This exact rifle, manufacturer part number RM400-16B-ROSE-R5X2, is chambered in 5.56 NATO and includes a factory-installed ROSE ROMEO5 Gen II red dot sight, a 16-inch barrel and two 30-round polymer magazines.

The rifle uses a black anodized receiver set with distinctive ROSE accents on key controls. Its operating layout will be familiar to AR-15 users, while ambidextrous controls and a reduced-angle grip make the rifle approachable from either shoulder. The result is a complete carbine package that can serve as a capable range rifle, training platform or home-defense option when configured and stored responsibly.

16-Inch 5.56 NATO Barrel

SIG equips the M400 ROSE with a 16-inch chrome-moly steel barrel and a 1:7-inch twist rate. The 5.56 NATO chamber supports common 5.56 ammunition and commercially loaded .223 Remington ammunition appropriate for the rifle. The faster 1:7 twist provides broad projectile-weight flexibility, making the carbine useful for general training and defensive loads.

The muzzle uses 1/2×28 threads with SIG’s tapered-shoulder interface and is fitted with a SIG flash hider-compensator. A mid-length direct-impingement gas system cycles the action. As with any rifle, ammunition, magazines and any installed muzzle device should be tested for reliable function before the firearm is relied upon for a specific purpose.

ROSE ROMEO5 Gen II Red Dot

A ROSE-branded ROMEO5 Gen II red dot is mounted on the rifle from the factory, providing a simple 1x electronic aiming solution for fast target acquisition. The receiver’s continuous top rail allows the optic position to be adjusted for the shooter’s preferred head position and eye relief. Because no separate iron sights are included, buyers who want mechanical backup sights can add compatible rail-mounted units without replacing the factory optic.

The red dot should be zeroed with the ammunition intended for regular use. After the initial zero, periodically verify the mount, battery and point of impact, particularly after transportation or accessory changes. Following SIG SAUER’s optic instructions helps preserve mounting security and battery performance.

Free-Floating M-LOK Handguard

The alloy handguard free-floats the barrel and provides M-LOK attachment slots for compatible accessories. A free-floating design prevents normal support-hand pressure and properly mounted accessories from bearing directly against the barrel. The slim profile gives the shooter multiple support-hand positions while leaving room for a light, sling mount, hand stop or other purpose-selected equipment.

Accessory installation should be planned carefully so that controls remain accessible and added weight does not unnecessarily upset the rifle’s balance. Any light or sling hardware should be tightened to the manufacturer’s specification and checked as part of routine maintenance.

Adjustable Stock and Enhanced Controls

A six-position Magpul MOE-SL stock allows the length of pull to be adjusted for different shooters, clothing layers and shooting positions. Overall length is approximately 33.25 inches with the stock collapsed and 36.5 inches fully extended. The rifle weighs approximately seven pounds before ammunition and additional accessories.

The reduced-angle grip supports a comfortable wrist position on a compact carbine. SIG’s flat two-stage Matchlite Duo trigger provides a defined first stage followed by a controlled break. Ambidextrous operating controls make administrative handling and shooting from either shoulder more convenient, while retaining the familiar manual of arms of an AR-pattern rifle.

Key Specifications

• Caliber: 5.56 NATO / .223 Remington
• Action: semi-automatic, mid-length direct impingement
• Barrel: 16-inch chrome-moly steel
• Twist rate: 1:7 inches
• Muzzle thread: 1/2×28 with tapered shoulder
• Muzzle device: SIG flash hider-compensator
• Optic: factory-installed ROSE ROMEO5 Gen II
• Handguard: free-floating alloy M-LOK
• Trigger: flat two-stage Matchlite Duo
• Stock: six-position Magpul MOE-SL
• Magazines: two 30-round polymer magazines
• Finish: black anodized with ROSE accents

A Ready-to-Configure M400 Package

The M400 ROSE arrives with the essential rifle, optic and magazine package already coordinated by SIG SAUER. Its adjustable furniture, ambidextrous controls, free-floating handguard and factory red dot provide a practical starting point that can be kept simple or configured with carefully selected accessories. Before use, read the rifle and optic manuals, clean and lubricate the firearm as directed, confirm the optic’s zero and observe all applicable magazine and firearm laws.