40 cal is the minimum legal roundball diameter for deer hunting in Maine. I think it is too small, only ~ 95 grains. I'd go to the 50 cal barrel. If its an original factory T/C barrel, it is a 1-48 twist (compromise twist for round ball and bullets). Try casting some LEE REAL bullets in 200g or heavier (I think the next heavier LEE REAL .50 is 250g). I've shot the lighter one,and it groups better than a patched round ball in the 1-48 twist (more mass too for more power). You can also get another Green Mountain barrel for the Renegade-a .54 round ball drop-in, and have a top notch meat getter.