paul,
i have been using spitfires for 2 years now and have taken 5 deer the only problem i have had is when i hit the shoulder on an entrance. my uncle also shoots spitfire he has a 60 lb. 30 in. draw shoots 224fps and has never had a problem with the spitfire although all his shots have been under 25 yards he has never hit the front shoulder so i can't speak on that part. as far as the quartering away shot goesthe lower exit hole really helps for tracking but as long as the broadhead cuts the lungs it causes a sucking chest wound which collapes the lungs hence the deer cannot breathe, it also causes the obvious bleeding in the lung which is what kills the deer quickly. I have never had a deer run over 80 yards that was a good double lung hit. hope this helps