So, if about 10 people in that theater had been armed...

[yardwork]

130. That's not what happened at Columbine, though.

The police stayed outside the school building for hours, and by the time they went inside with their firearms, Klebold and Harris had been dead for some time at their own hands.

I'm not seeing evidence that "in almost every case, these mass shooters stop their rampage only when confronted by people with guns," if by "people with guns" you mean civilians, not law enforcement. I understand that sometimes ordinary civilians with guns are able to stop mass murderers, but I don't see evidence that this is true "in almost every case."

In the incident with a mass murderer in my town, the shooter was stopped by a civilian with no gun. He tackled the gunman and knocked him down.

I'm not interested in banning guns. I recognize that this is a lost cause and a losing issue for Democrats. The country is awash in guns and that's the way it's going to stay. I think that our efforts would be better directed at improving mental health access. However, I don't think it's strategic of firearms enthusiasts to make exaggerated claims about the record of civilians armed with guns stopping mass murders. It happens sometimes but not all that often, actually.