I have been soley using muzzleloader for about 6 years now, this is what I have found:
Powerbelts=bad groups I believe due mainly to the gasket on the back of the bullet breaking up and acting as a rutter stearing the bullet off course reason why I think this is because I find chunks of the gasket all the way from the point of muzzle exit to the point of impact, just to much to risk on that big deer. Also of the 8 deer I have shot with power belts not 1!!! has retained even a 1/16th of its weight on impact, they shatter and NEVER go all the way through!!
Powder) regardless of what you read you will have much beeter results with a 100 grains of powder not 125 not 150, anything over 100 grains and you get an inconsistant burn of the extra powder, ya you could get a bit more power out of it but consistancy=accuracy!!
Always leave you gun out side and never reuse primers!! they are cheap and the greast weekness of the gun, I use a new one every time out!!
For peak performance check out Barnes line up of bullets, they are unstopable and deadly accurate!
Good luck I cant wait to get back in the woods with the ol’smoke pole!!
As for clean up i have switched to T/c all natural line up of petrolium based lubes and cleaners, takes me about 5 minutes-deailng of the breech plug.