4UANTUM MAGNUS PRO Precision TDC Hop Chamber (VFC/GHK AR) GBBPrecision machined from solid 6061 aluminium billet, The MagnusPro Hop Up chamber features a true vertical TDC (Top Dead Center) movement. This means regardless of your hop up setting, the pressure point remains in the same position for consistent results. Revolutionary self centring tri lug locking is the most effective design at not only centring the inner barrel but also holding it firmly in place! CNC bucking sleeve precisely centres the