"The only solution for a bad guy with a gun is a good guy with a gun"
Not to put too fine a point on it, but, Bullshit!
Never mind that as a maniac shot and killed 17 at Marjory Stoneman Douglas high school, the armed deputy stationed precisely for this reason cowered outside.
On the opposite end of the spectrum, this putz in Michigan needed to get a shotgun to deal with the fact that a 9th grader asked his wife for directions to his school, having gotten lost while walking there.
It is an effective way of dealing with crime when you consider that for the Rethuglicans of this ilk (i.e. the desperately frighted old white men) the real crime is being black or brown.