Firearms Trafficking to Mexico: Better Data and Performance Monitoring Would Help Agencies Direct Resources to Counter Cartels

What GAO Found Transnational criminal organizations (TCO) in Mexico seek to acquire semi-automatic firearms—AR-15s, AK-47s, and .50-caliber rifles—which they often convert to fully automatic firearms, according to agency officials. Armed with these weapons, TCOs pose a serious threat to Mexican law enforcement and military. TCOs acquire firearms from the U.S. primarily through straw purchasers—third parties who buy them on the TCOs’ behalf—and middlemen who smuggle the firearms through ports of entry on the border. U.S. agencies collect data on trafficked firearms, but some data have limitations that limit their utility. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) reported that 68 percent (82,785) of firearms recovered in Mexico and traced from January 2020 to December 2024 had a U.S. source. Department of Homeland Security (DHS) U.S. Customs and Border Protection (CBP) data show that CBP seized 4,944 firearms bound for Mexico at land ports of entry on the border from January 2020 through December 2025. However, CBP’s data system does not consistently capture information on the semi-automatic rifles sought by TCOs, and some officers may have difficulty identify...