GAO Says U.S. Agencies Lack Data and Performance Measures to Gauge Firearms Trafficking to Mexico

U.S. agencies trying to stop firearms trafficking to Mexico still do not have the data and performance measures needed to tell whether their efforts are working or whether resources are being directed effectively, according to a Government Accountability Office report released Monday.

The report says the scale of the problem is substantial even within the government’s partial data. Bureau of Alcohol, Tobacco, Firearms and Explosives trace data analyzed by GAO show that from January 2020 through December 2024, 122,084 firearms recovered in Mexico were traced, and 68% — 82,785 guns — had a U.S. source. Separately, Customs and Border Protection data show that from January 2020 through December 2025, CBP seized 4,944 firearms bound for Mexico at land ports of entry on the U.S.-Mexico border.

But GAO stressed that the ATF figure does not represent all firearms recovered in Mexico. It applies only to weapons Mexican authorities submitted to ATF for tracing. ATF, the only U.S. agency with legal authority to perform firearms traces, does not have visibility into every gun recovered in Mexico because Mexican authorities do not submit every weapon for tracing, and ATF cannot compel them to do so. That means the total number of firearms recovered in Mexico, and the exact number trafficked from the United States, is unknown.

The report, titled “Firearms Trafficking to Mexico: Better Data and Performance Monitoring Would Help Agencies Direct Resources to Counter Cartels,” describes the types of weapons U.S. officials say Mexican transnational criminal organizations seek: semi-automatic firearms including AR-15s, AK-47s and .50-caliber rifles. According to agency officials cited by GAO, those weapons are often converted to fully automatic fire.

GAO said the main ways firearms are acquired in the United States for trafficking south are through straw purchasers — people who buy guns on behalf of someone else — and middlemen who smuggle firearms through ports of entry along the border.

The trace data reviewed by GAO included 49,676 handguns, 32,601 long guns and 508 other firearms. CBP’s seizure data for outbound weapons headed to Mexico included 2,581 handguns, 2,147 long guns and 216 other types.

Several U.S. agencies share responsibility for trying to disrupt that pipeline. CBP conducts targeted outbound inspections at the border. Homeland Security Investigations, the investigative arm of the Department of Homeland Security, and ATF investigate trafficking networks. In Mexico, ATF assists with investigations and tracing, while the State Department’s Bureau of International Narcotics and Law Enforcement Affairs, known as INL, funds assistance to Mexican authorities.

GAO’s central criticism is that those efforts are not being measured in a way that shows whether they are succeeding. The watchdog said DHS has not established goals, desired outcomes, or performance measures with baselines and targets for its firearms-trafficking efforts. ATF, GAO said, discontinued measures it had established for Operation Southbound, its counter-smuggling effort. INL, meanwhile, lacks baselines, targets and results for some of its measures.

That gap matters because ATF and INL provided about $126 million for these efforts in fiscal years 2020 through 2025. Without stronger measurement, GAO said, agencies “do not know the extent to which their efforts are meeting objectives” and cannot determine whether they are directing resources to the most effective programs.

GAO also identified a specific weakness in CBP’s data collection. The agency’s seizure system does not consistently capture detailed information on the semi-automatic rifles sought by criminal organizations, the report said, and some officers may have difficulty identifying specific firearm types. GAO said that limits the government’s ability to generate useful intelligence on trafficking patterns.

The watchdog made four recommendations: improve CBP data collection so certain rifle types are easier to analyze; have DHS develop objectives and outcome measures; require ATF to develop performance measures for Operation Southbound; and have State and INL develop baselines and targets and collect results for their measures.

DHS disagreed with GAO’s recommendation on CBP data collection but agreed with the recommendation on performance measures. In comments reproduced in the report, DHS said, “CBP’s current processes allow officers to document firearm seizures that support CBP’s frontline interdiction mission and referral to appropriate investigative agencies.” GAO said it “maintains that this recommendation is valid.” ATF and the State Department agreed with the recommendations directed to them.

GAO noted that the issue has taken on added national security significance since the United States in February 2025 designated six Mexican cartels as foreign terrorist organizations and specially designated global terrorists. But the report’s conclusion was narrower: Until agencies improve data collection and set measurable goals, the government cannot say with confidence whether its anti-trafficking strategy is working or whether its money is being spent in the right places.