Brasonbrass, Well first off not all bolt action type muzzleloaders are ileagal. You just need to make sure the bolt doesn't cover the niple. With that said, I like the T/C Black Diamond style the best, as you know for sure the nipple is exposed. It's bult is on a sprin and you pull it back to cock it. The other types that you mentioned, the ones that are like a single shot rifel or shot gun, aren't legal. They cover the cap. Also a 209 promer isn't legal either. So make sure if you don't buy a BLack Diamond, you get one that has a conversion for a percussion cap. The black diamonds come with that already. I said this before, but if I were to buy a new muzzleloader today, it would be the black diamond. And the longer barrel helps burn magnum charges better nad gives you more velocity. Which will equal more enrgy. Hope this helps. I know there are a few out here that know a lot more than I do about muzzleloaders. I would go with the T/C Black Diamond. I don't think you will be dissapointed.
Buck