The best way to stop a person with a gun is a person with a gun. That’s why police officers carry guns. That’s why they call firearms the “great equalizer.”
We have hundreds of millions of guns in circulation currently in the United States. That makes the amount of gun violence beyond minuscule already. However, if you haven’t figured it out, most criminals and shooters choose locations where gun confrontation is absent…like school gun-free zones for example. If you arm and train the faculty and then change those stupid signs to this one instead:
…gunmen will most likely steer clear of that area.