Mexico City – Nearly half of the .50-caliber rifle cartridges seized in Mexico over the past decade have been traced back to a U.S. Army ammunition plant in Missouri, according to Mexican Defense Minister Gen. Ricardo Trevilla Trejo. The revelation, made during a presidential news conference Tuesday, follows an investigation by the International Consortium of Investigative Journalists (ICIJ) and its media partners into the flow of powerful ammunition used by Mexican drug cartels.
“According to the records we have,” Trevilla Trejo stated, “137,000 cartridges have been seized since 2012. Of those, 47% arrive from that company and have been sold in gun shops in the southern United States,” referring to the Lake City plant outside Kansas City, Missouri. The plant is the largest manufacturer of rifle rounds for the U.S. Military and a major supplier to American consumers.
The ICIJ investigation found that agreements between the U.S. Army and private contractors operating Lake City have allowed .50-caliber ammunition and components to enter the civilian retail market, ultimately reaching Mexican cartels. This includes armor-piercing incendiary rounds, despite congressional efforts to prevent their transfer to civilians.
Mexican authorities have recovered cartridges marked with Lake City’s initials, “L.C.”, at the sites of at least four attacks attributed to criminal organizations. These include the 2019 massacre of 13 police officers in Michoacán and an attack on the town hall in Villa Unión, where six people – four police officers and two civilians – were killed alongside 19 cartel members. The ICIJ first reported on the connection between the ammunition and cartel violence.
The use of .50-caliber weapons by cartels has escalated in recent years. As of spring 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) reported at least seven attacks on Mexican military and police helicopters using these guns, according to briefing materials. The weapons, which can weigh around 30 pounds and are nearly five feet long, have limited civilian applications but are readily available for purchase in U.S. Gun shops.
Since President Claudia Sheinbaum took office in late 2024, the Mexican government has seized 18,000 firearms, with 78% originating in the U.S. This included 215 .50-caliber rifles. Cartels have used these weapons to assassinate officials, attack security forces, and kill at least 121 people in 87 attacks since 2003, according to an ICIJ count.
While the flow of firearms into Mexico has been a long-standing concern, the volume of ammunition crossing the border remains less understood. The U.S. Currently has few federal restrictions on ammunition purchases by citizens and legal residents. The Army has contracted with Lake City’s operators to maintain a production capacity of up to 1.6 billion rounds annually, allowing contractors to sell excess production to foreign governments, law enforcement, and the public – a practice the Army claims saves taxpayers around $50 million per year.
The U.S. Government has made repeated pledges to curb the flow of weapons to Mexico. In September, Secretary of State Marco Rubio announced a fresh initiative to halt the trafficking of guns, and ammunition. However, a recent attempt by the Mexican government to sue U.S. Gunmakers for their role in arming cartels was blocked by the U.S. Supreme Court in June. A separate lawsuit against gun dealers in Arizona remains ongoing. The New York Times reported on the Supreme Court decision.
In comments Monday, President Sheinbaum indicated she is reviewing the ICIJ investigation and plans to formally question the U.S. Government about how military-grade weapons are entering Mexico.
