Prohibits use of new merchant category code by credit card companies for purchases of firearms and ammunitions.

New Jersey's bill A1251 prohibits credit card companies from using a new International Organization for Standardization merchant category code specifically for firearm or ammunition purchases. The law requires retailers selling firearms or ammunition to be classified under existing codes for general merchandise or sporting goods, rather than a separate "firearms" category. This prevents credit card processors from flagging or tracking legal firearm purchases through transaction data. The bill aims to protect Second Amendment rights and prevent potential privacy risks from financial institutions recording lawful gun purchases. It applies to payment settlement entities, merchants, and financial institutions processing card transactions in New Jersey.