American weapons have found there way into the hands of The Mexican cartels

 There is evidence that American military weapons, including machine guns, have been finding their way into the hands of Mexican drug cartels. This has raised significant concerns about how these weapons are being acquired and used by criminal organizations in Mexico.

The Mexican government has seized numerous military-grade weapons from drug cartels, including fully automatic machine guns and grenade launchers. Some of these weapons were identified as originating from the United States, either through illegal purchases or theft from U.S. military stockpiles  (American Military News)  (Wikipedia) .

Investigations have revealed that a portion of these weapons may have been diverted from legitimate sales to Mexican military and police forces. A U.S. State Department audit found that about 26% of firearms sold to these governments were later diverted to the wrong hands, including cartels  (Wikipedia) .

Additionally, operations like Project Gunrunner, including the controversial "Fast and Furious" program, have exacerbated the problem. These operations allowed firearms to be sold to suspected traffickers with the intention of tracking them, but many of these weapons ended up with Mexican cartels, leading to significant criticism and controversy (Wikipedia) .

Overall, while it is clear that American military weapons are ending up with Mexican cartels, the exact channels and scale of this issue are complex and involve multiple factors, including illegal trafficking and the diversion of legally sold arms.