U.S. Army Plant Ammunition Fuels Mexican Cartel Violence

Mexico City, Mexico — Mexican drug cartels have used .50 caliber ammunition produced at a U.S. Army-owned factory in attacks against police and civilians, according to an investigation by the International Consortium of Investigative Journalists and The New York Times.

On the morning of November 30, 2019, a convoy of trucks carrying gunmen armed with a heavy machine gun and powerful .50 caliber rifles entered the Mexican town of Villa Unión and opened fire. The men, sent on a mission to intimidate, planned to set the town hall on fire. Their firepower immobilized state and local police officers as they waited for military reinforcements. Terrified residents rushed for cover from the hail of bullets.

“The floor even shook when they fired,” said Luis Manzano, a Mexican journalist who arrived in the town by car during the shooting. “I had never experienced anything like that.”

The army eventually drove off the attackers. In the end, four police officers, two civilians, and 19 cartel members were killed. Investigators later collected at least 45 .50 caliber shell casings marked with the initials “L.C.” — corresponding to the Lake City Army Ammunition Plant, a sprawling facility just outside Kansas City, Missouri, owned by the U.S. government and the largest manufacturer of rifle ammunition used by the U.S. military.

Lake City has also been a major supplier of ammunition to U.S. consumers, including .50 caliber rounds. These powerful projectiles, the size of a medium cigar and designed for the military to destroy vehicles and light aircraft, are currently for sale to civilians across the United States.

Millions of pages of court documents, seizure records, and government data obtained by the ICIJ and The New York Times show how agreements between the army and the private contractors that manage Lake City have allowed .50 caliber ammunition and components manufactured at the plant to reach retail markets and fall into the hands of Mexican cartels.

The Mexican government has also purchased ammunition from Lake City, according to the documents, though they do not specify the caliber.

The domestic U.S. market for these cartridges is small: .50 caliber rifles, which have limited civilian application, typically retail for thousands of dollars, and heavy machine guns like those used in Villa Unión cost considerably more. Standard cartridges for these weapons cost between $3 and $4 each, and U.S. gun owners rarely buy them.

But in Mexico, where cartels have ample funds and an apparently insatiable appetite for .50 caliber firearms, these supplies are in high demand. Cartel members armed with .50 caliber weapons have shot down helicopters, killed government officials, fired on police and military forces, and massacred civilians.

Since 2012, the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives has seized more than 40,370 .50 caliber ammunition cartridges in states bordering Mexico, according to data obtained through public records requests. Lake City products accounted for about one-third of them, a larger share than any other manufacturer.

While .50 caliber ammunition from other companies, mainly in Brazil and South Korea, has also reached Mexican cartels, the data makes clear that the U.S. Army plant has been a major source of the destructive munitions used to wage military-style battles against Mexican law enforcement.

This includes an especially potent version of Lake City ammunition: armor-piercing incendiary cartridges, used in a 2024 attack on Mexican police and still sold online today.

In February of last year, the Donald Trump administration designated six Mexican cartels as foreign terrorist organizations, yet these same groups are acquiring ammunition manufactured at the U.S. Army-owned plant.

At least 16 online retailers have sold armor-piercing bullets manufactured at Lake City or made with components from the plant, according to a count by the ICIJ and The Times.

Vasily Campbell, owner of one such business, said he stopped selling the ammunition “about two years ago, when we found out where it was going and how it got there.” He said he grew suspicious when buyers began ordering 100-round boxes of ammunition for delivery to residential addresses. “That’s not a normal purchase,” he said. “There were several orders that I outright canceled.”

The U.S. Army did not respond in detail to questions about cartels’ use of Lake City ammunition. In an email, a spokesperson said allowing commercial sales from the plant has saved taxpayers about $50 million a year, primarily by reducing the government’s ammunition costs.

Successive presidential administrations have pledged to crack down on the flow of weapons to Mexico. And in September, Secretary of State Marco Rubio announced a new initiative with the Mexican government to stop arms trafficking into the country.

The number of .50 caliber cartridges seized is small compared to other calibers. But it is the power of .50 caliber ammunition, not its quantity, that has made it a game-changer for cartels, giving them the ability to outgun police and even the military, according to Chris Demlein, a former ATF agent who spent years investigating arms smuggling to Mexico.

“The impact a .50 caliber has in a firefight is staggering,” he said. These weapons allow cartels to attack targets at distances of more than a mile. “They really tip the scales.”

The ICIJ and The Times obtained investigation files from three episodes involving .50 caliber rifles, including the assault on Villa Unión. In each, Mexican authorities reported finding shell casings marked “Lake City.”

In a fourth example, in early 2024, gunmen used the most destructive variant — Lake City .50 caliber armor-piercing incendiary bullets — to attack a police convoy, according to a press conference by then-Defense Secretary Luis Cresencio Sandoval. One of the bullets pierced an armored vehicle, killing one crew member and injuring three others. “The armor we have cannot protect our personnel from this type of penetration,” he said.

Brenda Aparicio Villegas knows the devastating power of .50 caliber weapons well: her husband, Edder Paul Negrete Trejo, was a police officer who died on October 14, 2019, when he and his colleagues were ambushed in the western state of Michoacán. Authorities blamed the attack on the Jalisco New Generation Cartel.

Her husband and his colleagues, who often had to buy their own bullets, stood no chance against the cartel’s .50 caliber rifles, she said. Negrete, a father of three, died from a gunshot wound to the chest. Twelve other officers also died in the attack, including one who was burned to death. Investigators later found Lake City .50 caliber shell casings at the scene.

Not enough has been done to stop the flow of weapons and ammunition to Mexico, Aparicio Villegas said. “Unfortunately, many of us pay the price.”

Congress Bans Some Sales to Civilians

The .50 BMG cartridge was developed in the early 20th century for a heavy machine gun used to attack tanks and aircraft. For decades, .50 caliber shell casings were rarely found outside military training grounds and combat zones. However, that began to change in 1982 with the invention of the first .50 caliber rifle.

In the late 1990s, government auditors discovered that Talon Manufacturing Co., a contractor for the Department of Defense tasked with demilitarizing unnecessary ammunition, had sold a portion to civilian retailers, including more than 100,000 .50 caliber armor-piercing incendiary cartridges. Instead of scrapping the ammunition, the company had disassembled it and then manufactured new cartridges with the components.

Ammunition dealers told undercover government investigators that the armor-piercing bullets could shoot down a helicopter or penetrate an armored limousine. In effect, “the U.S. military is indirectly arming civilians with some of the most powerful and destructive ammunition in existence today,” a congressional report concluded.

In 2000, Congress passed a law prohibiting the Pentagon from selling armor-piercing ammunition for .50 caliber weapons to the public. It ordered the Department of Defense to require anyone receiving armor-piercing ammunition or components to pledge not to transfer the materials to “any buyer in the United States other than a law enforcement agency or other government agency.”

The legislation did not address standard non-armor-piercing cartridges, known as “ball rounds.” Talon continued selling that ammunition, manufactured with Lake City components, until 2007, when environmental and safety concerns led the company to cease operations.

Yet a new supply of Lake City ammunition soon emerged. Concerned about a potential ammunition shortage during the global war on terrorism, army planners allowed Lake City’s operating company, ATK, to increase the plant’s commercial activity in exchange for guarantees that the company would maintain the capacity to produce more than 1.6 billion cartridges a year. That included 60 million .50 caliber cartridges.

By late 2008, ATK had begun selling some of that ammunition to retailers.

A Surge in Violence

Authorities soon began intercepting Lake City ammunition bound for the southern border. In October 2009, U.S. officials seized 100 rounds of Lake City ammunition from a smuggling network that had brought hundreds of weapons, including at least one .50 caliber rifle, into Mexico. Authorities found the weapon in a raid on cartel forces that had attacked government officials, according to U.S. District Court documents.

Over the years, cartel violence incidents increased significantly, and attacks with .50 caliber weapons became more frequent. In May 2011, cartel members shot down a Mexican federal police helicopter in Michoacán state. A few days later, gunmen with weapons including a .50 caliber rifle fired on four other helicopters.

In the United States, Lake City was becoming a major source of .50 caliber ammunition. By 2013, boxes of 10 cartridges had become so common they could even be found in some Walmart stores. Online, cartridges linked together for use in machine guns were sold in 100-round boxes, identical to those used by the military, often at significant discounts compared to other manufacturers.

A popular website, Lucky Gunner, praised the power of Lake City ammunition: “If you want to stop a Jeep in its tracks, this is the ammunition you need.”

Starting in 2015, Mexico experienced a sharp increase in violence, with homicides rising for three consecutive years, according to official data. In border states, U.S. agents soon began monitoring bulk ammunition sellers as a way to detect arms smuggling operations, according to Jason Red, a former Department of Homeland Security investigator in Arizona.

“Our motto became: follow the ammunition and you’ll get to the guns,” Red said in a recent interview. “We tracked shipments from all over the country.”

The team seized hundreds of thousands of rounds of ammunition likely destined for Mexico, according to Red and court records. The vast majority were 7.62mm cartridges, the most commonly used in AK-47s, he said.

Seizures of .50 caliber ammunition were small and infrequent at that time, according to ATF and Customs and Border Protection records. But as U.S. authorities introduced new initiatives and increased resources to reduce arms trafficking to Mexico, the numbers grew.

Between 2019 and 2024, the ATF seized more than 36,000 rounds of .50 caliber ammunition in border states. Approximately one-third of them were identified as coming from Lake City. During the same period, customs officials seized nearly 21,400 units of .50 caliber ammunition. This included 2,850 armor-piercing incendiary cartridges.

Another Wave of Ammunition

In September 2019, the army awarded the $8 billion operating contract for Lake City to ammunition manufacturer Olin Winchester, which took over the facilities from defense contractor Northrop Grumman.

When Lake City changed hands, a small ammunition distributor, SGAmmo, negotiated the purchase of .50 caliber armor-piercing incendiary ammunition from Northrop Grumman. In a newsletter, the distributor’s owner, Sam Gabbert, urged customers to “buy before this gets banned,” adding that “this is one of those products that really surprised me when the deal closed.”

Another retailer, American Marksman, had also begun selling .50 caliber armor-piercing incendiary ammunition manufactured with Lake City components. Northrop Grumman had contracted the company to demilitarize unnecessary ammunition from Lake City, American Marksman wrote on its website, adding that it “gets many of its components from its Lake City recycling operations.” That included components for its armor-piercing incendiary bullets.

Olin Winchester’s policies on selling Lake City .50 caliber ammunition are unclear. The company’s catalog does not offer these bullets for sale to civilians. But Lake City cartridges and components, including armor-piercing incendiary bullets and projectiles, have continued to appear on the market.

In March 2023, at least one online retailer was selling batches of armor-piercing incendiary ammunition, labeled with a code indicating they were manufactured by Olin Winchester at Lake City. And American Marksman still sells armor-piercing incendiary ammunition on its website. (It is unclear which Lake City contractor produced the components used to manufacture that ammunition.)

In January 2022, the Department of Justice announced the indictment of members of an arms trafficking network, led by a former U.S. Marine, that sold weapons and ammunition, including Barrett .50 caliber rifles, to the Jalisco cartel, the same group accused of killing Aparicio Villegas’ police officer husband. Four months later, the Marine pleaded guilty.

During the operation, U.S. federal agents seized approximately 10,210 .50 caliber armor-piercing incendiary bullets with Lake City markings. There is no indication the ammunition came from American Marksman or SGAmmo.

In an email, the army said Lake City contractors are “required to comply with all federal and state regulations governing the sale of commercial ammunition. While the operating contractor does not sell directly to the public, it sells to distributors, resellers, and retail stores, which are also required to comply with federal, state, and local laws regulating the sale of ammunition.”

Olin Winchester did not respond to a detailed list of questions about its operations at Lake City and its policies on selling .50 caliber ammunition and components manufactured at the facility. In an email, Northrop Grumman said it “fully complied with the government’s contractual obligations in its ammunition sales” during the two years it managed Lake City. SGAmmo did not respond to several emails about its .50 caliber ammunition purchases. American Marksman also declined to comment.

‘The Best Weapons’

The former mayor of Villa Unión, Sergio Cárdenas, was frying pork rinds in his butcher shop when he thought he heard the backfire of a car. It was a gun.

On the street, pickup trucks were passing by. On the doors, stamped in white capital letters, were the initials CDN: the Northeast Cartel. “I stand behind that freezer, where they can’t see me, right? And I watch them pass,” Cárdenas recalled. “You could hear the .50 calibers. Suddenly a bullet or two would whiz by here overhead. They break the air because they’re so big.”

As soon as the convoy passed, he slammed the shop door shut. The pork rinds were left burning. Outside, the streets fell silent as the entire town went on alert. People barricaded themselves in their homes for the rest of the day.

The cartel hitmen failed in their attempt to burn down the town hall. But they riddled it with bullets, as well as surrounding buildings, some leaving holes larger than a fist.

Authorities traced one of the .50 caliber weapons used in the assault to a Texas store. Investigators found that the owner had sold nearly 500 guns that ended up in the hands of the CDN, including a .50 caliber machine gun and at least six .50 caliber rifles. A federal court sentenced him to 10 years in prison after he pleaded guilty.

U.S. authorities charged 14 members of the arms trafficking network and confiscated more than 2,300 rounds of Lake City ammunition.

Upon learning that the .50 caliber cartridges he heard in Villa Unión came from an ammunition factory owned by the U.S. Army, Cárdenas did not seem surprised. “The drug traffishers get everything,” he said. “Well, they get the best weapons from the United States.”