California gun owners have long been besieged by a lengthy list of unjust, unconstitutional firearm laws that make practicing their Second Amendment right more difficult. And a new law that just took effect is going to make freedom even more scarce in The Golden State.

The new law, passed by the legislature last year and signed by anti-gun Democrat Gov. Gavin Newsom, required credit card networks to make a new firearm-specific Merchant Category Code (MCC) available to banks and other financial institutions by Monday.

At issue is a special MCC for gun and ammunition purchases adopted last year by the International Organization for Standardization. MCCs are used by payment processors (like Visa and Mastercard) and other financial services companies to categorize transactions.

Prior to the creation of the specific code for guns, firearms retailers fell under the MCC for sporting goods stores or miscellaneous retail. If the new code is used, credit card companies and other payment processors can tell the purchases were firearms, basically creating a de facto registry of firearms and firearm owners.

While many find that distasteful—even illegal—California Democrats and Newsom embraced the idea. Consequently, for any firearms or ammunition now purchased in California with a credit card, there is a record kept that it was for a firearm or related product.

As NRA’s Institute for Legislative Action has pointed out in the past, collecting firearm retailer financial transaction data amounts to surveillance and registration of law-abiding gun owners. Those promoting this scheme are in favor of firearm and gun owner registration. Consequently, it should be assumed that the goal of this program is to share all collected firearm retailer MCC data with government authorities and potentially private third parties that might include gun control organizations and anti-gun researchers.

Being able to know if a purchase was for a gun or ammo must sound like a great idea to Newsom and his gun-ban cronies, and a few other states have passed similar laws, including Colorado and New York. However, just as with many gun-related issues, while California seeks to punish gun owners, many states have sought to protect them from such overreach as the use of the new gun-specific MCC. In fact, more than a dozen states have passed laws outlawing the uses of such codes, including nine states—Indiana, Utah, Wyoming, Kentucky, Iowa, Georgia, Tennessee, Alabama and Delaware—just passed such measures this year.