This upper build has a Timber Creek lightweight 15” Mlok rail and a 16” carbon fiber tension 350 Legend barrel made by BSF. The muzzle brake is a SilencerCo ASR and the bolt is a Alex Pro Firearms with a nickel boron finish. The gas block is an adjustable Superlative, which makes it easy to tune the upper to different ammo and compensates for the back pressure of a silencer.