Depending on what material your stock is (laminate, wood or synthetic), glass bedding could improve your situation. Some other things to address ( as written to me by others here when I started asking) are to make sure your scope bases are good quality and tight, ditto on your rings, have a quality scope, get Knight to adjust your trigger pull to 2 1/2 to 3# and eliminate possible problems in your system that you can control before modifying your gun. I would strongly advise several range sessions with taking well detailed notes of loads, bench rest techniques, any other nuances, equipment and components so you do have a well established baseline. Dont get me wrong I hate writing any more than I have to but since I have been doing this I can put my finger on things that can change groups ( shooting with mouth open versus mouth closed is one). Once you have established this baseline I would suggest doing one part at a time, maybe starting with making sure the front end is free floated. Shoot and record. Now maybe the bedding of the recoil lug itself. Shoot and record. And it goes on and on, just do it slowly so you can say what helped and what didnt. I purchased a Miles Gilbert Bedrock kit from Midway ( can usually catch them on sale for $15) and it does have some really good directions but you will find none that are addressing Muzzleloaders. Im speaking from experience here in stating take it slowly and keep good notes.
