Core 15 Rifle Systems 100278 Base M4 Semi-Automatic 223 Rem/5.56NATO 16" 30+1 Black 6 Position Synthetic Stock Black Aluminum Receiver

CORE15 Mil-Spec Forged 7075-T6 M-4 Upper and Lower Receiver, Type III Class II Hard-coat anodized finish, M4 feed ramps, (1913 Picatinny rail flat top) with dry lube internal finish and laser engraved T-markings. 16" 4150 Chrome Moly M4 profile Chrome Lined Barrel 1:9 Twist, Chambered in .223/5.56 x 45 mm NATO, Direct Gas Impingement Gas System.