unless your getting a realy good deal on the barrel I woulden't see small increase in speed if any , out weighing the cost.
I shoot the 250gr SST's out of a 26" Encore with a magnum charge and I'm sure it'll get to 400yds but that would likely be the very max.
If your looking for a true long range muzzel loader I'd look at the Savage and use smokeless powders.
I didn't realize you could shoot smokeless powder in a muzzleloader. Guess I have some" learn'n " to do, before I decide on which muzzleloader to buy. Thanks for the response.