no more assault type rifle sales and no magazines that hold more than 7 rounds. At least the death toll would be lessened with less firepower. The assault weapons themselves seem to have a cachet that gives ammosexuals the feeling of power that they lack in real life.
And trump encouraging the alt right dipshits and inciting them with his careless Nuremburg rallies as president is a factor in some of the incidents, the manifestos prove that out. If trump were to shoot himself in the head outside his mental bunker the mass shootings would probably slow a bit.