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 an Alpha Shooting Sports 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. Alpha Shooting Sports is one of the major AR Parts manufacturer in the industry and they especially make great pistol caliber barrels. Feed cones on their barrels are larger to accomodate a larger variety of bullet types. The Bowden 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 from WL Armory, 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: 5 inch, 45 ACP Caliber, 4150 Chrome Moly Vanadium Steel, 1:16 Twist, Nitride/Melonite Treated - made by Alpha Shooting Sports HANDGUARD: 7 inch M-LOK Free Floated, Machined out of 6061 T6 Aluminum - made by Bowden Tactical GAS SYSTEM: Blowback System GAS BLOCK: Blowback System - No Gas Block Needed MUZZLE DEVICE: Kak Industry 5/8-24 Slimline Flash Can 100% MADE IN THE USA OPTIONAL: ADD a WL Armory 45ACP Nitride BCG