they are great on deer, A friend that I hunt with and I use them between the 2 of us in the past 3 years of using spitfires we have sucessfully killed 8 whitetails. Out of all the kills the furthest a deer has run after being hit with a spitfire was about 15 yards that was a double lung hit on a doe, the best kill was a shoulder hit on a buck the spitfire went clean through the shoulder blade cut the asophagus in two and put a nice slice through the heart the deer folded up and fell right where it was standing, the next day the same exact broadhead that killed that buck the day before after just cleaning it up a bit it killed a nice doe. The spitfire is an extremely durable mechanical broadhead I will never use anything else. They are also awesome on a turkey.