Looks to me like the Mexican armed forces and Mexican law enforcement are pretty well off as far as guns go. They also have armor, air support, artillery, crew served weapons, and uhmmmm. . . .what else was there. . . .oh yeah, US funding. That's helpful too.
It also looks like they could care less that H&K is no longer in the business of arming Mexican government personnel, and thus indirectly arming the cartels, considering that Mexico is using weapons from the likes of Beretta and FNH, and have even fielded their very own rifle for their military.
And while the Beretta ARX160 would probably be on the top of my list if I had to fight the cartels, I certainly wouldn't feel too inadequate to be outfitted with an FN FAL either. Wouldn't necessarily want to clear rooms with it, but for street fighting, yeah, give me the well worn four foot battle rifle that spits 7.62.