http://www.atf.gov/publications/news...er-2005-02.pdf

Under federal law, muzzleloaders are classifed as "antique firearms" and are not subject to the provisions of the Gun Control Act. According to the document listed above, individuals prohibited from posssessing firearms may purchase and possess "antique firearms", ie muzzleloaders. The catch though comes in the type of muzzleloader. If the MZ is built on a centerfire rifle frame, such as an Encore or NEF, it's considered a firearm and therefore illegal for a felon to purchase or possess. Also, if a MZ uses 209 primers, a felon can possess the actual MZ but the 209 primers are considered modern ammunition and therefore illegal for a felon to purchase or possess. Funny thing though, according to the ATF document listed above, a felon can possess black powder, percussion caps and "mini balls" as they are considered ammunition for "antique firearms". Now if state or local law prohibits a felon from possessing a muzzleloader or components of, the state law supersedes federal law. So, a felon may be in the clear under federal law, but may still be prosecuted for violating state or local laws if they apply.