Stop Arming Cartels Act of 2025

This bill expands the regulation of .50 caliber rifles under federal firearms laws and authorizes new civil remedies for certain violations. Firearms that are trafficked from the United States to Mexico are often routed to transnational criminal organizations (TCOs), including cartels. In recent years, TCOs increasingly use .50 caliber rifles in attacks on Mexican security forces. In 2025, in Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos , the U.S. Supreme Court held that the Protection of Lawful Commerce in Arms Act (PLCAA) bars a civil lawsuit by Mexico against U.S. firearms manufacturers and one U.S. firearms distributor for costs associated with gun violence in Mexico. (The PLCAA limits the civil liability of firearms manufacturers and sellers for damages resulting from the criminal or unlawful misuse of firearms.) This bill generally criminalizes the import, sale, manufacture, transfer, and possession of .50 caliber rifles under the Gun Control Act and subjects .50 caliber rifles to regulation (i.e., registration and licensing requirements) under the National Firearms Act. Additionally, the bill criminalizes the sale or transfer of firearms and ammunition to foreign individuals or entities designated as significant foreign narcotics traffickers or as part of their networks and sanctioned under the Foreign Narcotics Kingpin Designation Act (Kingpin Act). Finally, the bill creates an exception under the PLCAA to allow civil lawsuits against firearms manufacturers or sellers that knowingly sell or transfer a firearm or ammunition to a foreign individual or entity designated and sanctioned under the Kingpin Act.