First off mass shootings isn't just school shootings, it's criminals committing crimes. Build more prisons, prosecute the bad guys using guns to commit crimes. Defunding police has emboldened the criminals IMO. We have enough gun laws, now lets enforce them.
What has happened in the US to increase the school shootings or mass random shootings? There has to be more to it than too many guns. I think mental illness is a place to start.