gets even bettah! 
https://www.khon2.com/news/national/how-often-does-a-good-guy-with-a-gun-end-an-attack/
Andrew pointed out that even with Dicken’s rapid response, three people were killed, emphasizing that the best prevention strategy is one that stops bad guys from getting a gun in the first place.
One major issue that is flawed in those statistics is that not every State allows its citizens to carry so they have no other choice but to call LE for an armed response.
Yes, and if we could un- invent firearms and destroy every single one on the planet, people would still find ways to commit mass murder. Trucks filled with chemicals, bombs made in crockpots, IEDs, a moving vehicle down a crowded street of pedestrians, nerve agent, .... the list goes on. Making it HARDER for someone to kill dozens at a time doesn't PREVENT it from happening.
Sometimes all it takes is a well placed fire in a building with no easy exit/chained exits. Are we banning fire next?
Back to reality. Guns are here to stay. They need to stop focusing on the means and start looking at actually stopping the threat AFTER the murderer has decided to kill. Anything else is wishful thinking.
How many other failed "wars" does the US have to create for people to get a clue? We've had a war on drugs for decades. A war on crime in certain cities. There's a war on poverty. There has been a war on obesity. So many others, I can't even remember.
How have those efforts been at PREVENTING anything? I'd say they all have gotten better and worse over time, no thanks to government. Often the problems are tied to the economy or other factors not caused by the government.