The SIG Sauer M400 FORGE (brand part no. PM400-556N-11B-FORGE) is a 5.56 NATO AR pistol built around an 11.5-inch barrel and bundled with SIG’s ROMEO-MSR Gen II red dot, giving shooters an optics-equipped defensive pistol straight out of the box. Sig Sauer ships the FORGE with a 30-round magazine and ambidextrous safety controls, keeping the platform fast to run from either shoulder. The black finish and compact barrel length make it a natural fit for home defense and truck duty. Among AR pistols, the M400 FORGE favors shooters who want a SIG-built 5.56 pistol with the optic already included.

Key Specifications

• The chambering is 5.56 NATO.
• The barrel measures 11.5 inches.
• Includes a factory-bundled ROMEO-MSR Gen II red dot optic.
• Ships with one 30-round magazine.
• The safety is ambidextrous.
• The action is semi-automatic on the AR platform.
• Finished in black.

Frequently Asked Questions

Does this come with an optic? Yes, SIG bundles the ROMEO-MSR Gen II red dot with this FORGE package.

Can it shoot .223 Remington? Yes, a 5.56 NATO chamber safely fires both 5.56 NATO and .223 Remington ammunition.

Is this pistol an NFA item? No, it transfers as a standard Title I pistol — but adding a shoulder stock to its sub-16-inch barrel would create a short-barreled rifle requiring prior NFA approval.

Buy the SIG Sauer M400 FORGE AR Pistol

A SIG 5.56 AR pistol with the red dot already in the box is exactly what the M400 FORGE delivers. Order it from our Lubbock, Texas gun shop and we will get it to your FFL as soon as it is ready to ship.