Guntec US Made 9MM/45ACP Billet Flat Top Upper Receiver StrippedAR 9 Billet Upper Receiver is a quality, American made billet upper designed to be used on Pistol Caliber Carbine (PCC) builds. Most often PCC builds are either 9mm or . 45 ACP. This billet upper features a unique design that sets it apart from traditional forged upper receivers. Manufactured to exacting standards on five axis CNC machines from a solid block of aircraft grade aluminum, this stripped upper not only looks good it is built to last. No