I just got in from shooting my new Big Jim LB. She is shooting sweet with arrows that come in at 11.7. I usually don't shoot that heavy, but I loved how they were flying and smacking my target. I won't take a shot at game over about 20 yards anyway, but really try to keep it 15 or under. Trajectory is not a problem at this distance and any speed loss is not critical to me. Also, as Forester said, it makes for a quiet bow, and it seems to make the bow more stable. 10gpp is just a baseline. Some folks like going heavier, some like the extra speed from going lighter. You'll get great penetration with the heavier arrows. It's subjective, I wouldn't get hung-up on numbers. Experiment to see what feels good to you.