Thats debatable about being illegal since muzzle loaders are considered "Nongun" by the BATF. I know that sounds dumb but that is how they consider them that is why you can legally shoot homemade black powder cannons or morters or buy black powder guns through the mail. The only muzzle loaders that are affected and considered guns for legality purposes are the ones that have frames that can take other barrels like the Huntsman or the Encore ect. The Savage may fall under that too since it can use smokeless powder. Now if it was a Huntsman it would be illegal since there is a frame issue. I would think it would be legal for the sidekick as it is considered muzzle loader only. There are double barrel shotguns that have 14 inch barrels that are perfectly legal as they are muzzle loaders. TO be on the safe side I would call the BATF and ask.
