I personally use regular rifle scopes on every muzzle loader I've had, but they do make muzzle loader specific choices. The two main differences are that the parallax is usually set for 75 yards with shotgun/muzzle loader scopes, and if it's a BDC style reticle it's usually calibrated for a muzzle loader. Since most of my shots are 100+ yards, the 100 yard parallax of a rifle scope actually works better for me, and I don't really like the BDC style reticles and my muzzle loader scope doesn't have one in it, so that part doesn't matter to me either. Even if you do want that style reticle you can use the rifle scopes, you just will have to find out where each circle, or dot, or line depending on the scope hit's, and it may be at different ranges than the muzzle loader specific ones are set for.