SIG Sauer M400 Forge
SIG Sauer · Rifle · In Production · 2026
Also known as: M400 Forge, M400-FORGE, SIG M400 Forge
Overview
The SIG Sauer M400 Forge is an entry-level direct-impingement AR-15 introduced for 2026 that brings premium features to a sub-$1,000 price point. Its standout feature is a 16-inch cold-hammer-forged barrel produced on the same machinery SIG uses for the MCX, with a 1:7 twist and compressed grain structure for longer life and tighter bore tolerances than the button-rifled barrels typical of the segment. It comes equipped from the factory with a TriggerTech two-stage flat-blade duty trigger, a free-floating M-LOK handguard with a full-length top Picatinny rail, an ambidextrous charging handle, a six-position MAGPUL SL-K stock, and a ROMEO-MSR Gen II 2-MOA red-dot sight. The mid-length gas system softens recoil and the 1/2x28 muzzle is threaded for muzzle devices and suppressors.
Specifications
| Weight (empty) | 3084 g (108.8 oz) |
| Overall Length | 902 mm (35.51") |
| Folded Length | 819 mm (32.24") |
| Barrel Length | 406 mm (15.98") |
| Action Type | Gas Operated Direct Impingement |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Two Stage |
| Trigger Pull | 16 N (3.6 lbf) |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 905 m/s (2969 fps) |
| Muzzle Energy | 1640 J (1210 ft·lbf) |
| Effective Range | 500 m (547 yd) |
| Maximum Range | 3600 m (3937 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 5.56x45mm NATO · primary · 5.56x45mm NATO — also known as 5.56mm NATO, 5.56x45mm, .223 Remington
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety Selector, Ambidextrous Safety
- Features: Cold Hammer Forged Barrel, Free Float Handguard, M Lok Mounting, Full Length Picatinny Rail, Mid Length Gas System, Triggertech Two Stage Trigger, Ambidextrous Charging Handle, Magpul Sl K Stock, Romeo Msr Red Dot, Threaded Muzzle
Variants
- SIG Sauer M400 Forge Pistol — Pistol
Production
Production years: 2026-present
Origin
Country of origin: United States
Notes
Overall length 902 mm extended / approximately 819 mm with the stock collapsed. Ships with a 30-round magazine and the ROMEO-MSR Gen II red dot. A pistol variant with an 11.5-inch barrel and MAGPUL BSL arm brace is offered alongside the rifle.
Background
SIG Sauer built the M400 Forge's barrel on the very same cold-hammer-forging line that turns out MCX barrels, then priced the whole rifle under a grand - a deliberate jab at the idea that hammer-forged accuracy has to be a premium upgrade.