I have a 6x45 (6mm-223) upper. It has a DPMS receiver and gas block Model 1 Rifle Length Forearm 20" AR-Stoner 1-8" Twist SS Barrel The barrel is threaded, and the whole thing is extremely accurate. I am getting .5" or less moa from muzzle to 500 yards. Check out the 3 shot 200 yard .327" group. My proudest moment! This upper has had less than 200 rounds through it, so it is practically new. I have around $450 into this upper. Asking $375 obo. I will sweeten the pot with a set of RCBS 6x45 Small Base Dies. The scope and rings are not included. No BCG or Charging Handle Included.