I have to ask, why is 10gpp. seem to be the magic number? Shot a ton of deer shooting between 8-9gpp at weight from 42#s to 85#s and the deer never noticed. I think people get way to caught up in arrow weight, the priority should be to put it where ya want it and tune the arrow to fly perfectly, if you end up at 8gpp or 15 gpp. it makes no difference. Now Moose and some thick skinned critters it does but whitetail none. I myself shot the full length of a coyote and a big doe a few years back, shooting 40#s at 28.5"s and arrow weighed 312 grains. Shawn