I know that firearms manufactured before 1899 are generally exempt from federal firearms regulations, but I'm having trouble finding specific references to this in NFA stuff. Here's a little background. Though generally friendly to NFA items, Indiana state law disallows all short-barreled shotguns. However, this regulation doesn't apply to shotguns manufactured prior to 1899. I am having trouble finding an equivalent exemption within Federal law, though. It may be an issue of familiarity, or it may be an issue of volume , but I seldom have any trouble at all finding what I'm looking for in Indiana law. Federal law always baffles me though. Anyone have any knowledge and a citation? I would love to buy an old SxS and convert it to a short barreled snake destroyer, but I don't want to commit a felony. Thanks.