Me too, I say you can shoot a much lighter arrow to gain more speed, but there really is no maximum. Heavier means less noise from the bow. It'll just shoot a lot slower, that's all. And me, being a speed freak go for all I can get, within the realm of reason. My hunting arrows weigh 316gr and 3D arrows weigh 265gr, shooting 53 lbs. The speeds are 280+ and 308 fps respectively. For hunting I can sight in a single pin for 25 yards and shoot about anything within 33 yards by holding the middle of the chest cavity. I get about 3" drop at 33 yards. My spread between 20 yards and 30 yards is less than 2 1/2". Makes life kinda easy.