> And most of the market for weapons flow South; drugs flow north.
Oh really? "Weapons from the north" are semi-autos. They have autos. (No, they're not convertible.) They get them from their military (which is supplied by the US) and similar sources.
A source that says "x% of traced" doesn't tell you how they decided to trace. (Hint - they have an agenda.)
It's a side point, but many semi-automatic weapons can in fact be converted to fully-automatic mode with drop-in parts. Makes sense; if you think about it, it's actually harder to make an auto stop firing after the first round.[0] Manufacturers do take steps to make the parts incompatible, but only with limited success.
Of course those drop-in parts themselves are considered to be machine guns by the ATF, and are thus absurdly expensive and hard to get ahold of. A fully legal and transferrable drop-in auto sear[1] for an AR-15, which is a few ounces of machined steel that lets you use the automatic M-16 parts, would have had to be made before 1986, and these days goes for >$5000.
[0] See http://en.wikipedia.org/wiki/Sputter_Gun . The ATF's original definition of a machine gun was a firearm which shoots more than once with a single trigger pull. Someone entirely too clever for his own good came up with the idea of making a gun with no trigger, which fired continuously so long as it was loaded. These were, for a brief period, completely legal to build and sell (although none were sold).
[1] http://www.quarterbore.com/nfa/dias.html . See also the Lightning Link, http://www.quarterbore.com/nfa/lightninglink.html which is literally just a couple of interlocking strips of metal. Cutting a strip of metal in that way is a Federal felony that can nab you >10 years even if you do not possess the actual rifle. They really do take this stuff very seriously.
If they are getting weapons from the military (and they probably are as well since the Zetas are ex military) then why are they smuggling in from the US? [1]
Oh really? "Weapons from the north" are semi-autos. They have autos. (No, they're not convertible.) They get them from their military (which is supplied by the US) and similar sources.
A source that says "x% of traced" doesn't tell you how they decided to trace. (Hint - they have an agenda.)