The round ball is probably never going to make it for hunting from what I have seen so far. However, the conical seems to have promise. Long way to go though, so we'll see. Most of the fun is trying!
qajaq59,
Get yourself a good lead conical in the 430 to 460 grain class, and you will be surprised how well your 1:28 twist rifle will shoot them. Another option would be the 350 grain Hornady FPB's. These are from a 1:28 twist NEF Huntsman, it will shoot these bullets around MOA or under all day long. Forget the 385 gr Hornady Great Plains and Buffalo Bullets, they just never shot well out of any of my rifles.
From L to R; 350 gr Hornady FPB, 430 gr White Super Slug, 440 gr White Power Punch, 460 gr No Excuses, 480 gr White Super Slug.
All targets were shot with a 1:28 twist NEF Huntsman.