These are drop in replacements for your 223/5.56 Barrel to convert your AR-15 to 25-45 Sharps. The only thing you'll need to add is a flash hider. They are threaded 5/8x24 so they take any 308 flash hider on the market. These are button rifled, 4140 Ordnance Steel Barrels that have been Phosphated with their barrel extensions already attached. These barrels have a carbine length gas port, M4 feed ramps. These are in stock now.