I would bet that if you went to .452 bullets and sabot that groups would shring a little more yet. I always set my muzzleloaders up on a clean barrel and swab between shots until it's very clean before loading. You will get tighter groups and you won't need to worry about the fouled barrel stuff. Now your follow up shots won't be as fast but I never worry about a fast follow up shot because if the first one is right -- games over!