Will realistic gun control measures (not banning all weapons, let's not be ridiculous) stop EVERY mass shooting? No, of course not, but it will certainly lessen the body counts and prevent many. How is the fact that it won't stop EVERY attack an excuse for inaction? If that's reason enough for not having a law, why do we have any laws at all? Laws against pedophilia certainly didn't stop Sandusky. Let's just drop laws against it then, because it clearly doesn't work.
Ban assault rifles, high capacity clips, and hollowpoints; limit ammo that can be purchased in a given period, ban ownership of guns if you or somebody in your household is a felon or mentally ill, and create a thorough national background check that doesn't rely solely on what information is volunteered. Do any of those stop you from owning a gun? No (unless you have a disqualifier such as felony or mental illness). Will it prevent ALL mass shootings? No. Will it prevent some without infringing on your rights outside of not being able to go to a range with an assault rifle? Yes.
Of course, that's only PART of the problem. We also have to deal with mental health in this country, but good luck with that considering that's that godawful thing that Americans absolutely despise: the health of all citizens. Mental health treatment is extremely costly and most greedy psychiatrists don't take insurance (or are "out of network"). Are we ready, as a nation, to invest in the treatment of those with mental health issues? Hell no, that's er muny!! I really wish that wasn't the case.
Sadly, neither of these things will be addressed. Nothing will change. Our kids will continue to die and it is the fault of all of us, because we as a nation completely fail at protecting them. The blood of 20 kids and 6 adults is on all of our hands' due to our collective inertia, and it most certainly won't be the last. But enjoy your weekend at the range with that really cool assault rifle. Totally worth it!