Have a 16" 1-16 Twist BCA Dedicated 22LR Slick Side Upper Rear Charging Comes with 1 CMMG Magazine I put this on a Plumb Crazy Polymer Lower and it functioned flawlessly with CCI Standard Velocity, CCI Suppressor and Federal Auto Match $285 Shipped TYD.
Text 732-678-6706 to see a short Video of this upper functioning