Well I hate to take a whiz on the myth of heavier arrows being better for hunting but here goes. As far as I can see there is one..count em one benefit of a heavy arrow. It will make your bow a little quieter. As for kinetic energy and penetrating ability it has been my expierience that the differances are minimal. A given bow is capable of generating a given amount of kinetic energy. Sure a 500 grain arrow moving 260 fps will generate a lot more KE than a 350 grain arrow moving 260 fps. The problem is that a single bow won't shoot both weights the same speed. As you add weight to the arrow you lose speed. A heavier arrow may increae KE a little but not a lot. That being the case why not opt for the arrow that has a flatter trajectory. With a 100 grain muzzy on the tip ,my bow will blow a 357 grain (total weight) carbon express through a whitetail and bury it in the ground. Why would I change? The arrow can only pass through them once. It is also a myth that a faster arrow is less accurate. Once again, the arrows may change but the bow remains the same. My bow will shoot a light arrow or a heavy one with the exact same degree of forgiveness. This misconception stems from the fact that bows designed to be "Speed" bows are less forgiving. They tend to have low brace heights and radical cams that are not very forgiving of poor shooting form. So long as its straight and properly spined, an arrows weight will make no difference in the shootability of a given bow.