The SIG Sauer M400 Forge FDE is a 5.56 NATO AR-15 (SIG Sauer part no. RM400556N16BFORGEFDE) built to come out of the case ready to shoot, with a factory-mounted ROMEO-MSR Gen II red dot already zeroed for close and mid-range work. It runs a 16-inch cold hammer forged barrel with a 1:7-inch twist rate and a mid-length direct impingement gas system, threaded 1/2-28 and capped with an A2 birdcage flash hider. A TriggerTech 3.5-pound two-stage flat blade duty trigger gives shooters a clean, consistent break, while the full-length free-floating M-LOK handguard finished in FDE Cerakote leaves plenty of room for lights and accessories. An ambidextrous charging handle and a 6-position Magpul SL-K stock round out a build that weighs in at approximately 6.8 lbs with a loaded 30-round magazine, making the Forge FDE a well-equipped, ready-to-run carbine finished head to toe in Flat Dark Earth.

Key Specifications

• Chambered in 5.56 NATO for reliable, widely available performance.
• Fitted with a 16-inch cold hammer forged barrel with a 1:7-inch twist rate.
• Threaded 1/2-28 and fitted with an A2 birdcage flash hider.
• Runs a mid-length direct impingement gas system.
• Includes a TriggerTech 3.5-pound two-stage flat blade duty trigger.
• Ships with a factory-mounted ROMEO-MSR Gen II red dot with a 2 MOA dot.
• Wears a free-float M-LOK handguard finished in FDE Cerakote.
• Equipped with a 6-position Magpul SL-K stock.
• Fitted with an ambidextrous charging handle.
• Feeds from a 30-round polymer magazine.

Frequently Asked Questions

Does the M400 Forge FDE come with an optic? Yes, it ships with a factory-mounted ROMEO-MSR Gen II red dot with a 2 MOA dot.

What finish does it use? It’s finished in FDE Cerakote across the handguard and receiver.

What trigger does it use? It’s equipped with a TriggerTech 3.5-pound two-stage flat blade duty trigger.

Buy the SIG Sauer M400 Forge FDE

Shooters who want a ready-to-run carbine finished in Flat Dark Earth should look closely at the M400 Forge FDE. Order this SIG Sauer rifle from our AR rifle selection at Schaefer Defense, and we’ll ship it insured to your local FFL from our Lubbock, Texas shop.