I hate to burst some bubbles here, but rybohunter is right on this one, at least normal hunting distances (30 yds). If you don't believe it, get an archery program like The Archery Program (TAP), and compare the KE that your favorite bow will put out with different weight arrows. From 0 - 30 yds, the KE will darn near the same, no matter what weight arrow you use. Even at 50 yards, the difference between a 320 grain and a 520 grain arrow will be at most 3 ft lbs of KE with a 300 - 305 IBO rated bow.