I don't know why they can't just run a NICS check when you buy your Suppressor, Class 3 weapon, or SBR, and have the retailer charge an extra 200 dollars in tax for the stamp and send it in. A week later you get your stamp in the mail. Seems simple to me. If they want to know who has them they will know because you filled out the tax stamp form when you picked up your gun. Simple. I don't know what they hell they are doing for six months in the computer age.