Gun control won't stop school shootings. Many of the shooters are "borrowing" guns from family or friends.
But what really DOES cause school shootings? I think it is because we live in a society that is filled with fear and isolation. Human frailty turns fear into protection at whatever the cost. Isolation makes other human beings less than human. Add a agreement that violence is an answer to fear, and then individuals will take matters in their own hands. If we want to stop shootings, we should reduce the fear and isolation that many people feel.
Connect with others. Love your family, not matter what they've said or done. Get help for those who are mentally unstable. Pray for those who are weak.