Do I really have to start using the sarcasm tag? C'mon y'all =/
I didn't say automatic. The Kalthoff repeater existed 100+ years before the 2nd amendment was written.Somehow I don't see people bringing cannons to a school shooting.
As for automatic firearms: Oldest ones I could find are https://en.wikipedia.org/wiki/Mitrailleuse and https://en.wikipedia.org/wiki/Gatling_gun both of which showed up more than half a century after the 2nd amendment and I don't see a school shooter lugging those around either
https://en.m.wikipedia.org/wiki/Kalthoff_repeater
More importantly, I'm not sure what point you're trying to get at. Automatic weapons existed long before school shootings became a major problem. It's not someone invented a gun designed for shooting schools up in the 90s.