Gun Control does not work. Your own history is replete with high school rifle teams, Boy Scout marksmanship merit badges. You could buy rifles at hardware stores. You could order them - mail order - delivered to your home. Your country was awash in readily available firearms and ammunition. And yet in your past, you did not have mass school shootings. 

Other people have already expressed the question: "What changed?"

It was not that the availability of guns suddenly exploded or increased. It actually was decreased. What was changed, was societal decay.