ORIGINAL: nothinspecial
no difference in the frame, except the pro hunter is always stainless. All barrels, forearms, stocks etc are interchangeable.
on the pro hunter they made the "swing hammer" so you don't have to put a side hammer spur on to be able to cock the gun easy with a scope, the muzzleloader barrel has the "easy breach" where the specialty tool removes the breach with a 1/4turn, the rifle stock has a recoil reducer in it, and they come with 28''fluted barrels.
The Encore Endeavor (black powder)that is almost out in stores, takes the Pro Hunter andeasy breach one more step by allowing the breach to be twisted out with fingers instead of a tool.