You have to ask yourself why is the choice in the majority of these shootings the AR style of weapon?
Why is it that a gun is the choice to commit suicide?
Educate me. They kill more and are glorified in culture? What is your point though - if the AR didn't exist, would mass murderers not find a different weapon of choice? Regarding suicide, I'm guessing because it's instant and probably psychologically easier to pull the trigger than other options. However, I am not compelled to ban all guns due to this personal choice of suicide weapon.
I agree who owns it does matter. How they get these guns is another major problem.
Does anyone really believe the more guns in circulation makes everyone in the country safer?
Again, depends on who owns those extra guns. I would also say it depends on how many guns are already in circulation in that area. US obviously has more than enough guns, but only in general. But arguendo, should I care if in general more guns means less safety - should someone at personal risk ignore their safety because of a national cap on how many guns can be in circulation?