When any gun, 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 undetectable, can easily be melted down to prevent ballistics tests, https://judahsjxhn.blogofoto.com/45526992/high-production-proliferated-3d-printed-plastic-assault-weapons-ramping-up