I have no clue on how much you know about tuning so forgive me if I insult your inteligence. It could be alot of things. First it could just be you not knowing what your doing, it could be inproper arrow spine, vanes or fletchings could be not be steering enough, possilby getting fletching contact, man there is a ton of things it could be. Your best bet is to go into detail on your exact equiptment and what you have tried to do.