i had AWFUL experience with spitfires! the first buck i ever drew back on, i had a complete pass-through and not one blade opened. a friend of mine had the same thing happen to him. i switched to fixed blades and they suck too as far as i am concerned. i feel that your broadheads should fly identical to field tips with no tuning. so i switched back to mechanicals but this time i am using grim reapers. they do devastating damage and fly very straight. i also like the rocket steelheads. i have them as back ups.