I never said that making a thing illegal doesn't make it harder to obtain. As usual, you don't listen to anything but your own parroting.
What I said is that Johnny Nutjob would be able to go out and get a banned weapon with little or no effort despite your ban, since there are just so many of them on the street already. All you will do is restrict those who follow the law (and aren't your problem if you are concerned about safety). I also pointed out that, if you were truly concerned about the safety in schools, you would consider other, more effective solutions such as a guard, or better law enforcement proactive behavior for known trouble makers and criminals. But this would put the responsibility on the individual, not the inanimate object.
But hey, show us all those pictures of all the kids again - that's really emotionally moving. Unfortunately you ignore all the kids killed by gun violence in Chicago, or Detroit, or Philadelphia, or Baltimore, or...
Because it doesn't fit the narrative.