Like LBR just said, it's the "HIT FORCE" that kills, not the speed. You would want to go with as heavy an arrow as you can get. In your case the arrow weight comes in around 400 Grains @ 165 FPS for the 24# K.E. If you went to a 500 Gr. arrow and got 150 fps out of your bow your hitting with around 33# of force and that's plenty for deer.