After you have tried everthing, find somebody with a hooter shooter. This will make sure that its not the bow or setup. Trying a stiffer spin arrow should help but also take a look at your limb pockets! Remove your limbs and see how tight the pockets are to the riser? Then shim them so there is no slop. This should help tighten up your group down range. Check your timming on your cam (YES SOLO' S NEED TIMMED) ask your pro shop or call Mathews about the timming proceedure. Good luck and GOD BLESS!!