When any weapon, metal or organic, is sold as separate parts, such as sub-receiver, stock, barrel, scope, etc., they can serve non-weapon functions, and were never outlawed, and never can be. Plastic, even electro-magnetic guns with graphene circuits, are x-ray elusive, can easily be melted down to prevent ballistics tests, https://chancehxksy.blogzag.com/59414127/mass-proliferated-three-d-printed-plastic-assault-weapons-on-the-way