Mexican drug cartels' armament
There's been some claims from the present Administration that US firearms are going south and fueling drug cartels' wars. It is probably the case that some US handguns are being shipped south, but the serious armament of the cartels is now full-auto AK-47s, former Soviet RPGs, hand grenades and some American light antitank weapons. The sources of these are not gun shows or fun shops, but (1) central american countries such as Venezuela and the insurgent groups they support (2) the Mexican military itself (esp. the hand grenades) and (3) for the LAWs, thefts from American military bases. The last can flow south because for a $10-20 tip, you can get your car, and whatever is in its trunk, in without inspection.