Thanks for the additional explanation. I shoot GT7595s out of bowtech sc patriots. One is set at 71lbs, the other 74lbs. Both bows shoot at between 278-280fps. I have been shooting 100g slick tricks and would like to give the 85's a try. These arrows seem to have more than enough spine and the bows are well tuned. I can't imagine shooting past 50-55yds even under perfect conditions (I turned down a hell of a mule deer this fall at at 70 even though I practice out to 65). My bottam line is I want as stable and accurate arrows as possible so as to have one less variable. My calculations puts 271/2" shafts right at 9%FOC. Any thoughts? I'm assuming I'll have to wait till spring to check out accuracy and arrow flight at longer ranges when the weather permits shooting outdoors.