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When cartel members drove into the Mexican town of Villa Unión and opened fire in 2019, their superior weaponry quickly pinned down local law enforcement.
Sent on a mission to intimidate, they wielded a heavy machine gun and powerful .50-caliber rifles that left the town hall and surrounding buildings riddled with bullet holes, some larger than a fist.
"I watched them go by," Villa Unión's former mayor, Sergio Cárdenas, recalled. "You could hear the .50-caliber rounds. Every now and then, a bullet or two would whiz by overhead. They ripped the air apart because they're so big."
Though military reinforcements eventually drove off the assailants, four police officers, two civilians and 19 cartel members were killed. In the aftermath, investigators collecting evidence from the scene gathered dozens of .50-caliber casings stamped with the initials "L.C."
The letters stand for the Lake City Army Ammunition Plant, a sprawling U.S. government-owned facility just outside Kansas City, Missouri, that is the largest manufacturer of rifle rounds used by the American military. | 
