US Ammunition Plant Linked to Mexican Cartel Violence: ICIJ Investigation

U.S. Army Ammunition Plant Linked to Cartel Violence in Mexico

A United States Army ammunition plant is the source of nearly half of all .50-caliber rifle rounds seized in Mexico over the past decade, according to the country’s defense minister. The revelation comes after an investigation by the International Consortium of Investigative Journalists (ICIJ) and its media partners uncovered how the powerful ammunition has been utilized by Mexican drug cartels in attacks against both government forces and civilians.

Defense Minister Gen. Ricardo Trevilla Trejo stated during a presidential news conference that, according to official records, 137,000 cartridges have been seized since 2012. Of those, 47% originated from the Lake City plant and were sold in gun shops in the southern United States.

The Lake City Army Ammunition Plant, located outside of Kansas City, Missouri, is the largest manufacturer of rifle rounds for the U.S. Military and has been a major supplier of ammunition to American consumers for over two decades. Agreements between the U.S. Army and the contractors operating Lake City have allowed .50-caliber ammunition and components made at the plant to enter retail markets, ultimately reaching Mexican cartels.

This includes armor-piercing incendiary rounds, which remain available for public purchase despite Congressional efforts to prevent their transfer to civilians.

Investigative records obtained by ICIJ and its partners show that Mexican authorities discovered cartridges inscribed with Lake City’s initials, “L.C.”, following at least four attacks carried out by criminal organizations in Mexico. These incidents included a massacre of 13 policemen in the state of Michoacán and an attack on the town hall in Villa Unión, where four police officers, two civilians, and 19 cartel members were killed. During the Villa Unión attack, cartel members used .50-caliber rifles, with investigators collecting at least 45 casings stamped with “L.C.” from the scene.

The use of .50-caliber weapons by cartels has been escalating. As of spring 2022, these guns had been used in at least seven attacks on Mexican military and police helicopters, according to an ATF briefing.

Mexican authorities have long expressed concern over the flow of illegal firearms from the U.S., citing it as a major contributor to violence within the country. Since President Claudia Sheinbaum took office in late 2024, the Mexican government has seized 18,000 firearms, 78% of which originated in the U.S. This included 215 .50-caliber rifles.

These .50-caliber rifles, nearly five feet long and weighing around 30 pounds, have limited civilian application but have become popular among Mexican cartels. Cartels have used them to down helicopters, assassinate government officials, attack police and military forces, and carry out massacres, resulting in at least 121 deaths in 87 attacks since 2003, according to an ICIJ count.

While the trafficking of firearms into Mexico from the U.S. Has been widely reported, less attention has been given to the millions of rounds of ammunition experts believe are crossing the border annually. In the U.S., there are virtually no federal restrictions on the purchase of ammunition by American citizens and legal residents.

The Army has agreements in place with Lake City’s operators requiring the plant to be capable of producing up to 1.6 billion rounds of ammunition per year. In exchange, the contractors are permitted to use excess production capacity to sell ammunition to foreign governments, law enforcement agencies, and the public, reportedly saving taxpayers around $50 million annually.

The U.S. Government has made pledges to curb the flow of firearms to Mexico. In September, Secretary of State Marco Rubio announced a new initiative with the Mexican government aimed at stopping the trafficking of guns and ammunition. However, a recent U.S. Supreme Court decision blocked a lawsuit by the Mexican government against gunmakers, alleging they failed to adequately prevent their weapons from reaching cartels. A separate lawsuit against gun dealers in Arizona remains ongoing.

In response to the ICIJ investigation, President Sheinbaum stated she would seek clarification from the U.S. Government regarding how military-grade ammunition is entering Mexico. “How is it possible that these weapons, which are for the exclusive use of the United States military, are entering Mexico?” she asked.