SIG SAUER M400-FORGE California 5.56 NATO Rifle

Description

SIG SAUER M400-FORGE California-Compliant 5.56 NATO Rifle

The SIG SAUER M400-FORGE RM400-556N-16B-FORGE-CA brings the core performance features of the M400-FORGE platform to a factory California-compliant, featureless configuration. Chambered in 5.56 NATO and compatible with .223 Remington ammunition, this black semi-automatic rifle uses a 16-inch cold-hammer-forged steel barrel, a mid-length direct-impingement operating system, and a 1:7 twist. It ships with one 10-round magazine and is set up for shooters who want a modern sporting rifle with premium factory components already installed.

This exact California model is distinguished by its fixed Magpul stock and compliant grip configuration. A muzzle brake replaces the standard flash hider used on unrestricted M400-FORGE variants. Those details matter when comparing visually similar models, because the non-California M400-FORGE is normally supplied with a collapsible stock and a 30-round magazine. The correct manufacturer part number for this listing is RM400-556N-16B-FORGE-CA, with UPC 798681744138.

Cold-Hammer-Forged Barrel and Mid-Length Gas System

At the center of the rifle is a 16-inch cold-hammer-forged barrel. Cold hammer forging is used to create a durable bore and rifling profile suited to sustained service. The 1:7 twist rate provides broad compatibility with common 5.56 NATO and .223 Remington projectile weights. A mid-length gas system gives the rifle a smoother operating impulse than a comparable carbine-length setup, supporting controllability and dependable cycling.

The barrel is surrounded by a full-length, free-floating 15-inch aluminum M-LOK handguard. Free-floating the handguard keeps sling pressure, barricade contact, and mounted accessories from bearing directly on the barrel. M-LOK slots provide flexible mounting positions for lights, hand stops, sling hardware, and other compatible equipment, while the continuous top Picatinny rail supports backup sights, magnifiers, or alternate optics.

Premium Trigger and Included Red-Dot Optic

SIG equips the M400-FORGE with a TriggerTech 3.5-pound two-stage flat-blade duty trigger. The two-stage design provides a defined initial take-up followed by a predictable break, giving the shooter better control for careful shots without sacrificing practical handling. It is a significant factory upgrade over a basic mil-spec trigger and helps make the rifle range-ready without an immediate aftermarket replacement.

A ROMEO-MSR Gen II red-dot sight is included. Its 2 MOA aiming dot is small enough for deliberate shots while remaining quick to acquire at typical carbine distances. The optic mounts to the rifle’s top rail, and the receiver and handguard provide room to configure its position or add a compatible magnifier. An ambidextrous charging handle further supports operation from either side and makes administrative handling easier around a mounted optic.

Featureless California Configuration

The RM400-556N-16B-FORGE-CA is supplied as a factory featureless rifle with a fixed Magpul stock, compliant grip treatment, muzzle brake, and 10-round magazine. These components differentiate it from the standard telescoping-stock model. Buyers should still confirm current state and local requirements with the receiving dealer before transfer, because laws and compliance interpretations can change and may vary by jurisdiction.

The black anodized alloy receiver and black handguard give the rifle a clean, uniform finish. Controls follow the familiar AR-pattern layout, so operation, cleaning, and accessory selection are straightforward for shooters already familiar with the platform. The reduced-angle grip geometry and fixed stock are intended to preserve useful ergonomics within the compliance-focused configuration.

Key Features

• Manufacturer part number: RM400-556N-16B-FORGE-CA
• UPC: 798681744138
• Caliber: 5.56 NATO / .223 Remington
• Action: Semi-automatic, mid-length direct impingement
• Barrel: 16-inch cold-hammer-forged steel with 1:7 twist
• California configuration: Featureless compliant grip, fixed Magpul stock, and muzzle brake
• Capacity: One 10-round magazine included
• Trigger: TriggerTech 3.5-pound two-stage flat-blade duty trigger
• Handguard: 15-inch free-floating aluminum M-LOK with top Picatinny rail
• Optic: ROMEO-MSR Gen II with 2 MOA red dot
• Charging handle: Ambidextrous
• Finish: Black

With its forged-barrel durability, upgraded trigger, included optic, and factory compliance-focused furniture, the M400-FORGE CA offers a complete 5.56 NATO package for the range, training, and general-purpose ownership. Always follow the owner’s manual and safe firearm-handling practices, and verify transfer eligibility with a qualified local dealer.