The Sig M400 is a true AR-platform tactical rifle, designed for use in law-enforcement, military operations, or the sporting field, as well as in competitive shooting. The M400 provides unparalleled accuracy with a 16" chrome-lined and phosphate-coated 1 in 7" twist barrel for maximum durability and corrosion resistance. The M400's dependable direct-impingement gas operating system uses a rotating locking bolt. A 7075-T6 aircraft-grade aluminum forged lower receiver adds to the rifle's rugged reliability. Other features include a fire-control selector, an adjustable stock, an A2-type flash suppressor and rear sight, a Mil-Spec muzzle brake, an ambidextrous magazine release, and a 30-round M16-style magazine.