16-1/2" cold hammer-forged barrel with innovative coating for extreme long life (1x7" and 1x9" twist available). A2 "birdcage-type" hider to control muzzle flash. Adjustable, two-position gas-piston-driven system, for firing suppressed or unsuppressed. Tool-less quick-change barrel system available in 10.5", 14.5", 16.5" and 18" and in multiple calibers. Multi-caliber bolt carrier assembly quickly and easily changes from 223/5.56mm NATO to 6.8mm Rem SPC. Free-floating MIL-STD 1913 monolithic top rail for optic mounting. Fully ambidextrous controls include magazine release, bolt catch and release, fire selector and non-reciprocating charging handle. High-impact composite hand guard with heat shield - accepts rail inserts. High-impact composite lower receiver with textured magazine well and modular grip storage. Ships in oversized hard case for accessory storage, includes 30-round PMAG.