Don't mess with pellets! As Blaze said, loose powder will give you the best accuracy due to being able to more accurately measure your powder.
If it is legal where you hunt, go with Blackhorn 209 powder. You will be glad you did. Nothing is even close in performance. It's awesome powder. Minimal residue, so you won't need to swab between shots. My experience has been very consistent shot to shot velocities. Cleans up with normal centerfire rifle products, with products such Hoppe's 9.