Premium .300 Blackout Complete Upper Build/ Suppressor Ready Adjustable Gas System.This upper features a pistol length gas system with adjustable gas block to allow for a wode range of easy adjustment when running suppressed.- Gen1 HADES Hybrid Stainless Steel Muzzle Device.-16" Stainless Steel Heavy Barrel M4, made from 416R Stainless Steel. Chambered in .300 Blackout Caliber, Pistol length gas system, 1:8 twist rate.Fully inspected barrel guarentee 1" MOA @ 100yards. Inspected with CMMs and Air Guages.- 7075T6 Billet Aluminum PAMAX Upper Reciever.-M16 Milspec Bolt Carrier Group- 15" Billet Aluminum Keymod Handguard.-Billet Aluminum Extended Charging Handle.- Milspec Forward Assist- .750 Adjustable Gas Block / Side Adjustment-Milspec Stainless Gas Tube-Easy Install Dust CoverEvery complete upper reciever sold is custom made and fine tuned to each caliber. Each upper is test fired prior to shipment.