My Hills sharpen down to 157 grains, I agree they will soften the spine slightly when compared to 160 grain blunt. El Grande Grizzlies will do the same thing, but in my bows it only shows up in borderline spines on individual arrows. For example, if 55 with 160 broadheads are just right and a 52 will still be good with a blunt, but can possibly be slightly soft with the broadhead. On the other hand I have also found that broadheads tend to fly better and flatter for the weight than glue-on field points and blunts.