We looked at gun bans in the 90's. You know what they found? Had such a massively minuscule effect on crime and murder rates that the FBI said they were totally worthless. Did nothing to stop mass causality incidents as demonstrated by the columbine highschool shooting, as well as others.
And anyone who complains about normal capacity magazines, do you realize how dumb an argument that is? A person, with as little practice time as a weekend, can learn to effect a tactical magazine change, one where you use your primary or trigger hand to activate the mag realese allowing the empty to drop free while getting the fresh mag with your week hand, inserting it, and racking the slide/receiver, in as little as 1 to 2 seconds. That is a total of 3 to 6 seconds added to the total time to fire off 30 rounds, assuming a ten round limited copacity magazine. That is effectively pointless in a mass shooting attack.