Sig Sauer RM400556N16BFORGECA M400 Forge *CA Compliant 5.56 NATO 10+1 16" Black Anodized Alloy Receiver w/Picatinny Rail, M-LOK Handguard, Magpul MOE Black Polymer Stock, Shark Fin Grip, Sig ROMEO MSR

Note: This product must be shipped to an Federal Firearms Licensed Dealer(FFL Dealer)

Overview

The SIGM400 5.56 NATO Rifle with 16in barrel in Forge Black is a semi-automatic AR-platform firearm configured with a Romeo-MSR Gen II optic, fixed stock, and an AL MLOK handguard. It ships with a 10-round magazine and is built with forged components and a black finish for a clean, durable exterior.

Key Features

• Model: SIGM400
• Caliber: 5.56 NATO
• Action: Semi-automatic
• Barrel length: 16in
• Handguard: AL MLOK HG
• Stock type: Fixed
• Optic: Romeo-MSR Gen II
• Magazine included: (1) 10RD MAG
• Finish: Forge Black (BLK)

Specifications

• Product name: SIGM400, 5.56 NATO, RIFLE, 16IN, FORGE, BLK, SEMI, ROMEO-MSR GEN II, FIXED, AL MLOK HG, (1) 10RD MAG, CA
• Caliber: 5.56 NATO
• Barrel length: 16 inches
• Fire control: Semi
• Optic model: Romeo-MSR Gen II
• Handguard system: MLOK
• Stock type: Fixed
• Magazine capacity: 10 rounds
• Color/finish: Black, Forge finish

Benefits

• Integrated optic readiness: Romeo-MSR Gen II included for a streamlined setup.
• Modular handguard interface: AL MLOK HG supports accessory mounting via MLOK.
• Consistent handling: Fixed stock configuration supports repeatable shouldering.
• Capacity configuration: 10-round magazine included.

Use Cases

• Range sessions with 5.56 NATO ammunition
• General AR-platform handling with an optic-equipped configuration
• Training and practice where a 16in barrel and MLOK handguard layout are preferred

Why Choose This SIGM400

This SIGM400 configuration pairs a 16in 5.56 NATO semi-automatic rifle with a Romeo-MSR Gen II optic, a fixed stock, and an AL MLOK handguard in Forge Black, providing a complete, measurable package with a 10-round magazine included.