In some instances with rifle/bullets I like to stay off the shoulder. In others, like Idahorons, I like to take all measures I can to anchor the animal right there by busting both shoulders. So I do my best to use a bullet I know can handle both situations no matter how close the animal is. Max loading any BP rifle will usually result in poor performance in grouping and very little consistency in your first shot performance. My suggestion would be to ditch the pellets and go to loose powder. Next would be to try out the Lehigh bullets as Sabotloader suggested and if they don't shoot well, try out the 250gr or 300gr XTP bullets. In that black diamond of yours Bearbow, I would start out at 90gr with either of those bullets and work up to find where you are getting the best cold clean barrel consistency. Work it up by 5 grain increments. Grouping your rifles at the range is all well and good, but you aren't shooting for consistent groups at an animal. You are shooting that very first shot. So you need to know exactly where that very first shot is going to consistently hit.