Most of the weapons on the street in Mexico were originally in the possession of the Mexican Army. That is why Mexico won’t release the serial numbers of weapons they take from drug gangs, they don’t want to expose the source of the weapons as their own government.
Those same weapons were “donated” by the US government to help fight the drug war. Release of those serial numbers would also implicate the US Government.
IF the gangsters have H&Ks, then that is likely true. If they have AKs and ARs, it's much less likely. Their police maybe, I'm not sure what kind of rifles they use.
Now Greta is saying that AK-47s are not "small weapons", I guess the small weapons would be handguns and .22 rifles.
I hate to tell her, (NOT!), but AK's and for that matter ARs, are "intermediate power" weapons, in contrast to the H&Ks in 7.62 NATO that the Mexican Army used until recently. (They now use an indigious derivitive of a version of the 5.56 H&)
For comparison the H&K G-36