CMMG 30Bc40AMB Resolute MK4 300 Blackout 16.10", Midnight Bronze, M-LOK Free-Float Handguard For AR-Platform (No BCG Or Charging Handle) Top Off Your Next Build With This Resolute Mk4 Upper Group. Chambered, This Upper Group Is a Staple For Any Collection And Comes Ready To Pair With The AR15 Lower Group Of Your Choice. Caliber: 300 Blackout Barrel Length: 16.10" Receiver Finish: Midnight Bronze Handguards: M-LOK Free-Float Handguard Finish: Midnight Bronze Barrel Length Range: 16" To 16.99"