i shoot a parker hunter mag, 31" and draw weight is maxed (should be between 65-70#) I am currently shooting carbon wolverine 31" arrows (carbon express special model for walmart) i was getting extremely frustrated after i purchased a 7 pin sight and the buttom pin would only go to about 68 yards.....then it dawned on me that this arrow may be too heavy for further shots.....well i weighed it (on an ancient weigher) and got between 1 and 1.1 oz....so it is between about 437 and 487 grains....which i think is just too heavy...this arrows shoot fine for me out to 60 yards, but i would like to utalize the new sight and shoot out to 80...

the question i have is do each arrow manufactorer(i would prefer carbon) have there own determining chart for proper grain weight for my set-up or is it more universal?? if it is universal i went to an AMO web site (http://www.huntersfriend.com/arrowhelp/AMO-Minimum-Arrow-Weight-Chart.htm) --(i believe i am speed cam and choose 65-69# on the web site)and it says i should be at 477...which i am...so does this mean that i need to keep my arrow weight the way it is or can i get a lighter arrow so that i can shoot out to 80 yards?

thanks,
josh