We need a total ban on semi-automatic weapons and the devices that make them so effective at killing people. Many countries have tried this, and how has it worked for them? We need mandatory safety training, licensing and usage/storage requirements just as we do for vehicles. And we need mandatory and effective background checks to prevent 'deranged' persons from having guns of any type. Don't we already do?
The countries that have tried it (most recently Australia as the result of their first and last mass shooting) have found it to be very effective at reducing violent crime, particularly senseless mass shootings.
No, we don't have effective background checks. Duh.