The Brigade Manufacturing AR Complete 5.5 inch 9mm Upper Receivers are threaded 1/2x36.
The manufacturer does not state if the Brigade Manufacturing AR Complete 5.5 inch 9mm Upper Receiver can handle +P ammo or not. However, most manufacturer do not recommend firing +P ammunition through their barrels. I recommend contacting Brigade Manufacturing for that information.
The Brigade Manufacturing AR Complete 5.5 inch 9mm Upper Receiver must be paired with a Brigade Manufacturing, or equivalent AR9 lower receiver that uses the LRBHO functionality as this upper itself does not have a LRBHO function.
These Brigade Manufacturing AR Complete 5.5 inch 9mm Upper Receivers will not include a BCG or charging handle.
These Brigade Manufacturing AR Complete 5.5 inch 9mm Upper Receivers will not include a BCG or charging handle.