Your having pass through problems becuase your using heads that are to large for your setup. The buckblasters are huge, and the spitfires are good sized as well. switch to a moderate sized head and make sure your bow is tune well. Scorpions,Steelheads, Rocky snypers and Ironhead xp' s and the Vortex 100 grn steel with a 1 1/2" cut should all work well and provide pass throughs on resonable shots. To answer the original question, what frank said is 100% correct. You can also go to my website www.broadheadtests.com and find some usefull info on choosing the correct broadhead.