The letter and the directions they sent me say:

" We reccomend that you tune your bow with 100 grain field points first, then unscrew those and screw on tallons and shoot. Please note that they will group just as the 100 grain field points."

I have been reading on some of the other forums and all of the reports so far are these heads are doing exactly as they claim. One person even said they didn' t make a better mouse trap they reinvented the wheel.