In short, muzzleloaders can be shipped to your door without having to go through an FFL (state and city regulations might affect that). The long answer is Section 921(3) of the “Gun Control Act of 1968” says a firearm is “any weapon which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; the frame or receiver of any such weapon; any firearm muffler or firearm silencer; or any destructive device. Such term does not include an antique firearm.” Here’s the catch; modern muzzleloaders are classified as “antique firearms” as they are replicas of pre-20th Century designs and have limitations.