Doegirl is right on, but unfortunately so is Articap.

Fortunately for me Arkansas must have had someone with common sense at the Legislature one day and they ignored it completely. If it is recommended by the manufacturer of your muzzleloader, in Arkansas you are clear to go. I have noted a couple other states that now use the "manufacturer's recommended powder" as their definition. Wish they all would do so as it would surely make it a lot easier to answer the question posed here.