Mexico’s government says that almost half of the high-powered .50-caliber ammunition seized from drug cartels over the past decade can be traced back to a U.S. government-owned factory.

According to Mexico’s defense secretary, Gen. Ricardo Trevilla Trejo, authorities have confiscated about 137,000 .50-caliber rounds since 2012, and 47% originated from the Lake City Army Ammunition Plant in Missouri. The facility, owned by the U.S. government, is the largest producer of rifle ammunition for the American military — but it also allows commercial sales through private contractors.

That means ammunition originally manufactured for military purposes can end up in civilian retail markets. Investigations found that armor-piercing rounds from Lake City have been sold online and in gun shops in the southern United States — and later trafficked into Mexico.

Since President Claudia Sheinbaum took office in October 2024, Mexican authorities have seized 18,000 firearms, nearly 80% traced to the U.S. Among them: Barrett .50-caliber rifles, grenade launchers, and machine guns.

These weapons have been used by cartels to shoot down helicopters, ambush military convoys, and terrorize civilians.

Mexico has repeatedly urged Washington to curb the flow of U.S.-made weapons, arguing that reducing cartel firepower is essential to lowering violence on both sides of the border.