The Spike's Tactical ST-15 LE Complete Upper is a duty-grade 5.56x45mm NATO assembly designed for the M4 Carbine platform. It features a 16 M4 profile chrome moly vanadium barrel with a black phosphate finish and a 1:7 twist rate. Built on a forged 7075-T6 aluminum receiver with a black finish, this AR Style unit includes a 9 BAR2 free-floating M-LOK handguard and a standard 1/2-28 threaded A2 flash hider. Weighing 4.30 lbs, this complete upper comes fully equipped with a Mil-Spec M16 bolt carrier group, a low-profile ST Micro gas block, and a carbine-length gas system for reliable cycling. Note: The ST-15 LE series is engineered to full Mil-Spec standards, offering the same level of quality and performance required for law enforcement use to the civilian market.