Muzzleloaders should shoot black powder. No matter what the ignition system is. I'm using Swiss in the Accura MR. I like the smell, smoke, and accuracy of BP. It even has it's own unique boom to it. It also has the lowest ignition temperature of any powder. It always goes off.

What's not to like? Dirty? Bah, muzzleloaders are dirty. Shoot a CF rifle if you want clean.

Be a muzzleloader hunter. Make big booms. Make big smoke. Make big smiles.