Its really simple actually, I found the simpler words for you.
That crazy guy, with the crazy idea honestly didnt just wake up and decide hes going to shoot up a theater (OBVIOUSLY SOME DO) ... that crazy person is pre-meditating, weighing his risks, and considering how many people he can kill...
Very simple, so simple, your that crazy guy, your selecting where you want to shoot up... are you going to shoot-up a church if I told you everyone in that church had a gun, or are you going to the gun-free zone where you can do insane insane damage... The answer is obvious...
So from that, we just realized, that yeah, more guns, equal less killings, and less shootings..
Your only rebuttal to this is to bring up some specific situation... or disregard the number of PREVENTED shootings, PREVENTED deaths that happened from each separate shooting...
Also, I am selling gunentry.com for wherever they want their population to submit their firearms for data entry to be listed legally from their iphones by sending pictures of their guns.. I dont know lol.