[Wonder Warthog]

"Mexico’s army is finding belt-fed machine guns, rocket launchers and grenades that are not sold for civilian use in the United States."

"Mexico's army" is likely the source of a lot of them...

[Ruy Dias de Bivar]

I remember during the Obama admin that Mexico was complaining about US made weapons there(Fast and Furious). But they also complained about cartels using South Korean hand grenades.
They also had large numbers of other weapons from other places, but only the US made weapons were mentioned.

Now where did the cartels get those?