I would think you would need a new forarm as the muzzleloader takes much larger screws than the reg. barrels, and the hole spacing may be different although they do look the same. You would have to get some washers to keep the smaller screws from going through the forend, hardwear stores carry flat washers that are large with small holes and then you would have the hole in forend where ramrod goes.
Deaconllb