Gearheart
I have reloaded since 1965 and have found several max loads that shot the best but with center fires its not the norm. I really don't relate that to muzzleloading. Because of the original CVA's firecracker barrels and the lawsuits that resulted the safety factor insisted on by the powder and arms companies is out of sight. There for unless you do your own pressure testing and enough information to do your own figures on your guns how do you know what maximum is?
It is very difficult even for those of us that do have the right equipment because of the arms co. not being willing to furnish information on just what the breach plug design will hold up to. Lee