I was told to steer clear of the Grim Reapers by a local pro shop. I originally was worried about penetration with Spitfires , but I have blown easily through most of the deer I've shot. This year I actually passed through a shoulder and broke the spine on a nice buck with a Spitfire(he was trying to duck my arrow). I have a friend who also uses Spitfires and has taken some deer and a nice black bear with them,all pass throughs. I shoot about 75# of KE , he shoots about 62# .Spitfires are the sharpest broadheads I have purchased out of the package(I've tried many) and the bloodtrails are awesome.Hope that is some help.