The ferrule of the Bloodrush broadhead is machined with aircraft grade aluminum using a 26 degree twist. This twist dynamic is effective at multiplying soft tissue displacement when either moving forward, or rearward, through the internal cavity of big game animals. Secondly, by taking advantage of integral ferrule â??blood portsâ?쳌 the process of blood loss is actually multiplied and enhanced as the blood fluid is displaced across a larger surface area. This combination of both ferrule twist and port suction creates a scientific phenomenon similar to a whirlpool or fluid vortex. 1 3/8 Inch cutting diameter.