When any gun, metal or organic, is sold as separate components, such as sub-receiver, stock, barrel, scope, etc., they can serve non-weapon purposes, and were never banned, and never can be. Plastic, even electro-magnetic guns with carbon circuits, are x-ray elusive, can easily be melted down to prevent ballistics tests, https://louisjwcdm.blogmazing.com/16885186/mass-produced-3d-printed-plastic-assault-guns-on-the-way