From Free Republic:

It wasn’t sporadic.  It was continuous throughout the city.  For a country that bans guns I thought, how in the world did they get their hands on all these full-auto weapons?  Clearly what sounded like M16 fire was prolific along with 7.62 x 39 AK autos with a smattering of smaller caliber full-autos, most likely 9mm.  Gun fire can be heard in most American cities on New Years, but I’ve never heard full-auto weapons being fired, at least not in the San Diego area.

The next day I went into work and sat down with a trusted senior Mexican manager.  I looked at him and said, “I thought guns were illegal in Mexico.”  He chuckled and said, “So you stayed in town last night?”  As the conversation progressed, it became clear that guns are as common in Mexico as tamales at Christmas.  Everyone he knows, including himself, own at least one gun.  And, it matters not whether it’s a semi-auto or fully automatic, they’re all illegal, so why stop with semi-autos?  Though clearly illegal in the states in most instances, a lot of Mexicans have more firepower in terms of military weapons than we can only dream of owning here.

This article first appeared in 2009. The author describes how no one in Mexico is unarmed despite it being illegal to own a gun larger than .22.