AR-15 Milspec 7075 T6 Aluminum Stripped Upper Receiver w/M4 feed ramps - Forward Assist and Ejection Port Door installed Kak Industry 18 inch 7.62x39 Mid Length 1/9.5 Twist Melonite 4150 CMV Barrel Low profile Nitride STEEL gas block Stainless Steel Mid length gas tube JE Machine Tech 15 inch Keymod Slim Profile Free Float Rail Standard 5/8-24 A2 Flash Hider and crush washer Azimuth Technology 7.62x39 Full Auto Nitride BCG and Standard Charging Handle Unbranded AR ELG Lower Parts Kit M4 Milspec Stock Kit *Optional*: Upgrade to a SOPMOD stock *Optional*: Upgrade to an Adjustable Gas Block *Optional*: Upgrade to a Black or Stainless Competition Muzzle Brake *Optional*: Change to a Magpul FDE Receiver and 15 inch HC Handguard (See Pictures for example) (choose from options above) We only use quality parts from reputable manufacturers in the industry. Kak Industry makes very high quality barrels. Made out of milspec 4150 CMV and melonited for enhanced corrosion resistance and lubricity. The JEMT Rail is very high quality and comparable to many other higher end rails that cost 2x or 3x as much. Handguard is lightweight, made from high quality 6061 aluminum and mounting system is rock solid. Gas Block diameter is 0.750 and is made out of steel (not aluminum). *Optional* - Upgrade to an Adjustable Gas Block. Great option if you are using suppressor or just want to fine tune your system. *Optional* - Upgrade to a SOPMOD stock. *Optional* - Like a Magpul FDE colored receiver and hanguard instead? We now offer an Aero Precision Upper Receiver and 15 inch Guntec HC Keymod Rail in Magpul FDE color (see pictures) - choose from options above. *Optional* - Upgrade to a Black or Stainless Competition Muzzle Brake. This is an enhanced version of the popular style muzzle brakes. The baffles and ports are milled larger to drive pressure up and to keep the muzzle down more effectively.