FIRST: Mass shootings in one form or another have always been a thing, especially school shootings. The very first American school shooting was back in the 18th Century during "Pontiac's Rebellion".
SECOND: Years ago; The average American civilian didn't have a bunch of military grade weapons that ensured mass death. We are not interested in banning all guns. We just want to ban the big stuff that YOU, A MERE CIVILIAN, DO NOT NEED! We also want permits, back ground checks and safety measures.
THIRD: The Second Amendment basically states that it's establishing a military for the country and that militias approved by the U.S. Government have the right to guns. It doesn't say that everyone has the right to a rapid-fire automatic death machine of doom.
FINALLY: You crave unfettered, high-powered stuff that would make even Al Capone blush because you want to overthrow the U.S. Government (despite the 2nd Amendment implying that it's PRO-U.S. Government). You are idiots. You honestly think you would have a chance against a VAST MULTI-TRILLION-DOLLAR BEHEMOTH OF COUNTLESS SOLDIERS, TANKS, BOMBS, MISSILES, DRONES, AIRCRAFT CARRIERS, FIGHTER JETS, COMPUTERIZED THINGAMABOBS OF ALL TYPES?
Look, Bub; The Colonists were only able to trash the mighty, superior British forces because they both used the same weapons technology, were more technologically matched and France was helping us out. You are not "David". The U.S. Govt. is not Goliath....it is Kali-Mata x 100!
So; Give it a rest! Find a more constructive way to deal with your inadequacy and accept that non-white, non-christian, non-heterosexual, non-male people are good and worthy of equality with you.