Aero Precision APAR700702M4: This complete upper includes Aero Precision's new ATLAS R-ONE Handguard! The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Aero Precision's proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards. This complete upper does not include BCG or Charging Handle.Includes: M4E1 Threaded Assembled Upper Receiver 9" ATLAS R-ONE Handguard 10" .300 Blackout CMV Barrel Low Profile Gas Block and Pistol Length Gas Tube Product comes assembled The muzzle brake that comes with this complete upper receiver is NOT pinned nor welded to this barrel.