I think Cloud 9,mn has the best way to come speed. I shoot about a 430 grain arrow and that is only at 10 gr/in. Just a quick guess but you must be shooting around a 480-500 grain arrow. You should be able to nock of at least 30 grains and possibly 50 if you are shooting 125 heads and switch to 100 grain heads. This should still leave you with a pretty good arrow weight. Don' t you just love it when you aska question and people give you good advice so you can go out and spend more money