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 350 LEGEND upper kit starts with a Gibbz Arms LEFT HANDED G4 Non Reciprocating Side Charging Billet Aluminum receiver, mated to a Tactical Kinetics 18 inch 350 Legend, Carbine Length Gas System, 1:16 Twist, Medium Profile, 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. 350 Legend - Introducing the World's Fastest Straight Walled Hunting Cartridge. Built with hunters and sport shooters in mind, 350 Legend is versatile on the range and in the deer woods. Tactical Kinetics is one of our major partners and they produce high quality, accurate barrels. 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. Comes with the P2A LEFT HAND Bolt Carrier Group. Also included is a lower parts kit and M4 stock kit to turn your stripped lower receiver into a full pistol or rifle. SOPMOD stock by JE Machine Tech is OPTIONAL. Features a wide cheek weld, rubber non slip butt pad, two water tight storage compartments and stainless steel QD swivel mount. Made in the US. SPECIFICATIONS UPPER RECEIVER: Gibbz Arms LEFT HANDED G4 Non Reciprocating Side Charging Billet Aluminum Receiver with Gen 2 Handle, M4 Feed Ramps, Type III Hardcoat Anodized Black (Gibbz Cam Pin Included) BARREL: 18 inch, 350 Legend Caliber, 4150 Chrome Moly Vanadium Steel, 1:16 Twist, Medium Profile, Nitride/Melonite Treated - made by Tactical Kinetics HANDGUARD: 15 inch M-LOK Free Floated, Machined out of 6061 T6 Aluminum - made by Bowden Tactical GAS SYSTEM: Carbine Length, Direct Impingement, Stainless Steel Tube GAS BLOCK: Low Profile Gas Block, Machined out of 4140 Steel MUZZLE DEVICE: Standard A2 Flash Hider with Crush Washer BOLT CARRIER GROUP: LEFT HAND, 350 Legend Caliber, M16 Profile, Mil-Spec, MP Tested, Nitride Treated, Properly Staked Gas Key, 8620 Steel Carrier, 9310 Steel Bolt LOWER PARTS: UNBRANDED AR ELG Lower Parts Kit STOCK: M4 Milspec Stock Kit - includes M4 stock, standard buffer spring, 3oz buffer, castle nut, latch plate and pistol buffer tube. 100% MADE IN THE USA OPTIONAL: UPGRADE STOCK to a JE Machine Tech SOPMOD Stock