I switched feildpoints going from a 100 gr. to a 125 gr. Out of curiosity, I put them throught the chrono......Well suprisingly (to me anyway) I lost 10 fps going to the 125 gr.........W/ the 100 gr. tip I was consistently getting 280 fps (375 gr. arrow) and w/ the 125 grain I was consistently getting 270 fps (400 gr. arrow) I was expecting to lose 5 fps or so but not 10 fps....I' m not really that concerned about the speed....280 and 270 is all the same to me but my concern is whether I' m dealing with a spine issue...i.e. the 125 gr. is creating much more ossilation due to weaker spine thus resulting in speed lose........Visually they fly perfectly (both arrows) and actually group together very nicely out to 35 yards and then the 400 gr. starts dropping a couple of inches.......I guess I' m just curious as to what you all think about the scenerio.......which ever one shoots best with BH is the one I' ll shoot so the weak spine issue could come into play.....10 fps seem like a big lose for only a 25 gr. increase in weight?