Brand: Sig Sauer
Model: M400 Forge
Platform: AR-15
Caliber: 5.56 NATO
Gas System: Mid-Length / Direct Impingement
Barrel Length: 16"
Barrel Description: Cold Hammer Forged Steel
Barrel Finish: Black
Capacity: 30rds
Twist Rate: 1:7
Muzzle Thread: 1/2 x 28
Muzzle Device: Flash Hider
Stock Description: 6 Position MAGPUL SL-K Stock
Stock Material: Polymer
Grip Description: Sig Overmold Grip
Grip Material: Polymer
Furniture Finish: Black
Upper Receiver Material: Alloy
Upper Receiver Finish: Black
Lower Receiver Material: Alloy
Lower Receiver Finish: Black
FCG: TriggerTech 3.5 Pound Two-Stage Flat Blade Duty Trigger
Rail Description: 15" w/ Full Picatinny Rail
Rail Material: Alloy
Rail Finish: Black
Attachment Style: M-LOK
Safety: 2-Position
Bolt Carrier Group: Yes
Charging Handle: Ambidextrous
OAL: 32.25" - 35.5"
Weight: 6.8 lbs
Includes: ROMEO-MSR Gen II with 2MOA Red Dot

Features

SIG Sauer M400 FORGE

The SIG Sauer M400 FORGE is a modern 5.56 NATO semi-automatic rifle engineered for durability, precision, and enhanced shootability. Built around a 16-inch cold hammer forged barrel with a mid-length gas system, this platform delivers consistent accuracy and a smooth recoil impulse across extended use. The rifle is equipped with a TriggerTech 3.5-pound two-stage flat blade duty trigger, providing a crisp, predictable break that supports improved control and shot placement.

Finished in Black, the M400 FORGE features a 15-inch M-LOK handguard with a full-length Picatinny rail for versatile accessory and optic mounting, including the included ROMEO-MSR Gen II red dot with a 2 MOA reticle. An ambidextrous charging handle enhances usability for a wide range of shooters, while the 6-position Magpul SL-K stock offers a compact, adjustable fit. Designed for adaptability and performance, this rifle combines premium components with a rugged, field-ready configuration.

Sig Sauer ROMEO-MSR Gen II

The Sig Sauer ROMEO-MSR Gen II red dot sight is built for reliable performance in a durable, streamlined package suited for a wide range of shooting applications. Its ruggedized industrial design withstands demanding conditions while maintaining consistent function. The parallax-free optical system supports fast target acquisition and improved accuracy, while the included see-through riser mount allows co-witness capability with iron sights.

A rotary illumination dial provides 12 brightness settings, including 10 daylight and 2 night vision-compatible options for adaptability in various lighting conditions. Powered by a common CR2032 battery, it delivers up to 35,000 hours of runtime. With IPX7-rated waterproof and fog-proof performance, this optic maintains clarity and reliability in challenging environments.

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It is the customer’s responsibility for understanding state laws regarding all purchases made. For a comprehensive list of all Shipping Restrictions, please refer to our Shipping Restrictions By State Page found Here.

All NFA Rules Apply

These items are controlled by the U.S. Government and authorized for export only to the country of ultimate destination for use by the ultimate consignee or end-user(s) herein identified. They may not be resold, transferred, or otherwise disposed of, to any other country or to any person other than the authorized ultimate consignee or end-user(s), either in their original form or after being incorporated into other items, without first obtaining approval from the U.S. government or as otherwise authorized by U.S. law and regulations.

Magazines will be removed from firearms when shipping to states with magazine capacity restrictions.

California 10+ Round Magazine Buyers: PSA values your freedom and constitutional rights above all else. However, PSA will not accept new orders nor will ship any order until the Ninth Circuit Federal Court of Appeals mandate becomes finalized. Once this mandate is finalized, we will start accepting new orders and ship 10+ round magazines to California Customers.

WARNING: Handling firearms or firearms parts can expose you to lead and other petroleum products known to the State of California to cause cancer, birth defects, or other reproductive harm. Wash hands thoroughly after handling. For more information go to www.p65warnings.ca.gov (CA Health and Safety Code Section 25249.6).