ORIGINAL: Jeff K
ORIGINAL: PatriotDually
I am shooting 72#'s with 29" draw and 570 grainarrows, so i am producing about 120lbs of KE. But yea i hear you need about 55lbs to shoot the Nap spitfires.
Actually that is 128 Lbs of KE, but I mean come on I don't think you are flinging a 570gr arrow at 318fps that is a bit ridiculous, a IBO rating for your bow is 326-334, remeber IBO system uses a 350gr arrow at 30" draw and 70lbs pull. Ok your arrow is 220gr more than that and 30gr more than the AMO rating which is 540gr at 30" and 60lbs pull. Mathematically I don't think that 2 lbs pull difference from the IBO testing is going to catapault you to 318fps, not to mention you lose speed when you decrease your draw length. If I had to guess a speed, it would be about 265fps-290fps, no more because of your outstanding arrow weight, which would put you at 99 lbs of KE. You lose speed at 29" draw, you lose speed because of the arrow weight, and you gain a little back at 72lbs pull.
Hmmmm i guess you are right Jeff, being im pretty new to this my bow was chrono'ed when i first bought it, only had a peep site and i was shooting his arrows at that time. They were carbon extremes not axis, so they were lighter, but the only thing that has changed since then is i added a loop and the heavier arrows so i did prolly loose about 20 feet or so. Im headed over there today to get my arrows re-fletched, ill get him to shoot it thru the chrono today and see what she is doing
