In responce to AllenRead, Im not sure what it is your hunting but I have never had an issue with lack of penetration on white tail deer. I have shot a couple that have field dressed 250 plus pounds and penetration wasnt an issue using a 365 grain arrow at around 300fps. I dont see the point in going with a super heavy arrow to get better penetration if you dont need it. Stay with the medium weight arrow that is fast and benefit from the flat trajectory. You said you couldnt think of a situation where better pentration wasnt the best option, put the arrow where it needs to be and it shouldnt matter. If you dont have time to range an animal or it happens real fast, that faster/flatter shooting arrow will help keep it in the kill. Just for an example, I shot a deer last year that would have probaly weighed 275 or more on the hoove. 50 yards quartering hard away. The arrow entered just behind last rib and stopped on the leg bone of the offside shoulder. I was shootinga easton axis shaft tipped with a wasp boss bullet for a total weight of 365 grains at approximately 310 fps. Do you think a 500 grain arrow would have snapped that leg bone and blew threw it, I doubt it.