The Optima is a good gun. It would be like a slightly upgraded Wolf with a longer barrel. They have a very good reputation for accuracy. I don't own one, but I've heard pretty much only positive reports about them. The Accura would be an upgrade on the Optima, with a better barrel. But the Optima is a good rifle too.

Oh, I'd recommend getting a .50 cal instead of a .45. I have a .45 and love it, but if you are new to muzzleloading, the .50 is more versatile and much, much easier to find bullets/sabots for.