Armored vehicles, explosive devices and grenade launchers, oh my!

Where are the cartels getting all that hardware? Must be all those damned American gun shows. Even though most of that stuff is highly illegal in this country without the accompanying paperwork. I saw a link to a podcast in which the Mexican ambassador to the United States said we needed to stop the flow of guns to Mexico, but "he says he is not challenging the Second Amendment." Somehow I am absolutely certain he mentioned some sort of new gun ban, though. If anyone wants to take the time to listen to it, be my guest, but I'm pretty sure nothing in there has not been put forth by the Mexican government before.