Starting with the SigM400 carbine, the Sig improved take on the direct impingement AR-style rifle, a B5 Systems SOPMOD 6-position telescoping stock, pistol grip, and Keymod carbine handguards are added in gray or foliage. The SIGM400 B5 Pistol also sports the B5 grip and Keymod handguards. Featuring 1:7 twist with Nitride treated barrel, the SigM400 B5 carbines and pistols are machined from 7075-T6 aircraft grade aluminum and are finished in hard coat anodize finish. Both come with Sig locking flip-up rear sights and have M1913 Picatinny flat-top upper receivers.
- Action: Semi-Automatic
- Caliber: 223 Remington/5.56 NATO
- Barrel Length: 16"
- Capacity: 30+1
- OAL: 32.3"-35.6"
- Weight: 6.7 lbs.
- Stock: Foliage Green 6-Position Collapsible
- Metal Finish: Black
- Muzzle: A2 Flash Hider
- Receiver Material: 7075 T6 Aluminum
- Sights: F Marked Front, Flip Up Rear
- Twist: 1:7"