SIG M400
SIG Sauer, Inc. · Carbine · In Production · 2011
Also known as: SIGM400, SIG Sauer M400, SIG M400 Enhanced
Overview
The SIG M400 (SIGM400) is an American direct-impingement, gas-operated, semi-automatic carbine chambered in 5.56x45mm NATO. Built on the AR-15 platform by SIG Sauer, it pairs forged 7075-T6 aluminum upper and lower receivers with a 16-inch chrome-lined barrel and a 1:7 right-hand twist. Standard features include a flared magazine well, ambidextrous magazine release, M1913 Picatinny rails, adjustable iron sights, quick-detach sling points, and a collapsible stock. Introduced as SIG Sauer's flagship modern sporting rifle, it later spawned the popular M400 TREAD and M400 Forge variants.
Specifications
| Weight (empty) | 3203 g (113.0 oz) |
| Overall Length | 902 mm (35.51") |
| Barrel Length | 406 mm (15.98") |
| Action Type | Gas Operated |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Action |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 940 m/s (3084 fps) |
| Muzzle Energy | 1767 J (1303 ft·lbf) |
| Effective Range | 500 m (547 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 | Hard Coat Anodized |
Calibers
- 5.56x45mm NATO · primary · 5.56mm NATO — also known as 5.56 NATO, 5.56x45mm, .223 Remington (chamber compatible)
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety, Extractor Support Pin
- Features: Direct Impingement Gas System, Chrome Lined Barrel, Forged 7075 T6 Aluminum Receivers, Ambidextrous Magazine Release, Flared Magazine Well, Picatinny Rail, Adjustable Iron Sights, Quick Detach Sling Points, Collapsible Stock
Variants
- SIG Sauer M400 TREAD - Modern Sporting
- SIG Sauer M400 Forge - Modern Sporting
Service history
Operators
- Civilian sport shooters
- United States law enforcement agencies
Production
Production years: 2011-present
Marketed primarily to the civilian sport-shooting and law-enforcement markets; later expanded into the M400 TREAD and Forge product lines.
Origin
Country of origin: United States
Designer: SIG Sauer
Notes
The base M400 accepts standard AR-15/M16 magazines and uses an M4-style feed ramp. An extractor support pin guards against over-pressure conditions.
Background
The M400 was SIG Sauer's entry into the crowded AR-15 modern sporting rifle market, leveraging the company's manufacturing base in Exeter, New Hampshire. Its TREAD sub-line, named for the company's 'Free Yourself' branding, became one of the most commercially successful budget-tier AR-15 carbines in the United States.