Out the box - Pantheon Arms Kentri 3.5N AR-15 Short Buffer System

Works out of the box. These are sturdy and of good quality have them on two builds already purchased another one for a 300blk build. Works flawlessly on the 223/556 and the 7.62x39 with 5.5 inch barrels. Only down side is that they don’t come with a castle nut and end plate despite that I still recommend!