All our uppers are carefully assembled and tested and ready to go out of the box. Every component is chosen to ensure a high quality upper is produced. Every upper is custom built to order and we go the extra mile to ensure the finished product is to your specifications. This 45 ACP upper starts with a Gibbz Arms G9 Non Reciprocating Side Charging Billet Aluminum receiver, mated to a Hitman Industries 7.5 inch 45 ACP, 1:16 Twist, Nitride/Melonite treated barrel. The Gibbz Arms receiver is a proprietary patented receiver that has a non reciprocating side charging handle - handle stays forward during cycling. Side handle is on the opposite side of ejection port allowing the shooter to quickly charge or recharge the weapon without taking finger off the trigger and eye off the scope. Hitman Industries is one of our major partners and they especially make great pistol caliber barrels. Feed cones on their barrels are larger to accomodate a larger variety of bullet types. The Axis Rail is a free floated system, M-LOK slots on all three sides, full length picatinny rail at the top, lightweight handguard. Barrel Nut is made out of solid steel to ensure a solid mounting system. Bolt Carrier Group is OPTIONAL. We offer a 45 ACP BCG, full auto profile, Properly Heat Treated, 8620 Single Piece Bolt, Nitrided. SPECIFICATIONS UPPER RECEIVER: Gibbz Arms G9 Non Reciprocating Side Charging Billet Aluminum with Gen 2 Handle, Type III Hardcoat Anodized Black BARREL: 7.5 inch, 45 ACP Caliber, 4150 Chrome Moly Vanadium Steel, 1:16 Twist, Nitride/Melonite Treated - made by Hitman Industries HANDGUARD: 9 inch M-LOK Free Floated, Machined out of 6061 T6 Aluminum - made by Axis MFG GAS SYSTEM: Blowback System GAS BLOCK: Blowback System - No Gas Block Needed MUZZLE DEVICE: Standard 5/8-24 Slimline Flash Can 100% MADE IN THE USA OPTIONAL: ADD a P2A 45ACP Nitride BCG