Brownells is proud to offer our customers a huge savings with this AR-15 Critical Build Kit. This kit includes every component necessary to build an AR-15, excluding the lower receiver. With the quality components sourced from some of the biggest names in the industry, you can have confidence that your finished rifle will be rugged and reliable. Includes 16” Nitrided M4 barrel with sight tower, A2-type flash hider,front sight kit, barrel nut, delta ring assembly, handguard, Melonited gas tube, upper receiver, M16 bolt carrier group, forward assist assembly, ejection port cover assembly, charging handle, lower parts kit, and carbine stock assembly. Lower receiver not included.