Why? Because of the raging drug wars on the Mexico-US border.
90% of weapons recovered in Mexico are smuggled in from the US. So, they smuggle drugs one way and guns the other, the guns being bought by straw buyers in the US first.
The AG says rifles and AK’s need no paperwork when sold in quantity but derringers do and that this is nonsensical.
As for legalization, he sidesteps the issue a bit but says the vast bulk of drug cartel money comes from marijuana and we as a country need to talk about this. Now.