I think aussie guy is going a little overboard with his set up, but to each their own. A 75 grain head is fine, what you need to look at is over all arrow weight and speed to see what kind of KE your getting. The only thing about a 75 grain head is its hard to get a good FOC. Two years ago I was shooting easton axis 400 arrows with a wasp 75 grain boss bullet. My FOC was around 10% I believe and I could have shot through a deer length wise if I wanted. I was getting about 75ft-lbs of KE.