My old arrows are carbon buck-eyes 435grains FOC is 10.3 My new arrows are Easton axis 420grains FOC is 9.3 both are fletched with 5 inch helical and are cut to the same lenghth my rest is a muzzy zero effect. The axis hits the target 2 inches lower than the buck-eye at 20 and 30 yards. this means i will have to move all my pins down for the axis but what i want to know is why would a lighter arrow impact lower than a heavier one????I have spin tested both no wobbles?? does the FOC have anything to do with it??