The way to end guns in school is not to have more guns in schools. Some have advocated arming teachers. It would be just a matter of time until a teacher mistook someone for a bad guy and shot him. And how long do you think it would take for some mischievous fifth-grade boys somewhere in the country to find a teacher's gun?
Even adding armed part-time police to school duty would inevitably lead to a tragic "mistaken identity" shooting.