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

S 1705 prohibits credit card companies from using a special merchant category code (MCC) to identify firearm or ammunition purchases. It requires these transactions to be classified under general merchandise or sporting goods categories instead, preventing credit card networks from flagging lawful firearm purchases. The bill directly affects payment processors, banks, and firearm retailers by banning the use of a new MCC proposed by the International Organization for Standardization. This prevents financial institutions from tracking or categorizing firearm sales separately, which the bill argues could lead to profiling of law-abiding gun owners.