Payment card networks (the systems behind credit and debit cards, like Visa or Mastercard) would be barred from using a special code that flags a store as a gun shop when you make a purchase—instead, gun retailers would have to be coded the same as general or sporting-goods stores. This means banks and card companies couldn't automatically track or separate out purchases made specifically at gun stores. The Department of Justice, the federal agency that investigates and prosecutes violations of federal law, would be responsible for enforcing this rule and would have to publish a yearly report on any investigations or legal cases that come from it.