Dave, this will sound crazy to you but one thing you might try with your current load is to add about 20 grains by volume of fine ground corn meal over the powder before seating the bullet. You are pushing that bullet pretty hard and probably would get better accuracy by cutting about 20-30 grains off the charge.

If the idea of the corn meal is too much, try a bore-button.

Maxi-Hunters seem to do less well than plain ol' Maxi-balls by most reports.