; requirements Section 922 of title 18, United States Code, is amended by adding at the end the following: (aa) (1) The Congress finds and declares the following: (A) Firearms tracing is the systematic tracking of the movement of a firearm recovered by law enforcement officials from the first sale of a firearm by the manufacturer or importer through the distribution chain (including the wholesaler and retailer) to the first retail purchaser. (B) Law enforcement agencies across the country work with the Bureau of Alcohol, Tobacco, Firearms, and Explosives to trace firearms and thereby obtain investigative leads in the fight against violent crime and terrorism. (C) The ability of law enforcement agencies to trace a firearm is dependent on the serial number or other marks on the firearm that identify the manufacturer or importer who manufactured or imported the firearm and that are unique to the firearm. (D) Interstate gun trafficking interferes with lawful commerce in firearms and significantly contributes to gun crime. Of the 211,384 firearms traced by the Bureau of Alcohol, Tobacco, Firearms, and Explosives in 2016, 60,936 of those firearms were originally sold by a licensed firearms dealer in a State other than the State where the firearms were recovered. These guns made up 28.8 percent of all firearm recoveries in 2016. (E) Even before the sale of a firearm, the gun, its component parts, and the raw materials from which they are made have considerably moved in interstate commerce. (F) If unserialized and untraceable firearms may be constructed and transported freely from State to State, ordinary citizens and foreign visitors may fear to travel to or through certain parts of the country due to concern about violent crime and gun violence, and law enforcement agencies may be unable to address it. (2) (A) Except as provided in subparagraph (B), it shall be unlawful for any person to manufacture, sell, offer to sell, transfer, purchase, or receive a ghost gun in or affecting interstate or foreign commerce. (B)