Here's the thing: guns are REALLY SIMPLE MACHINES. A gun can have fewer moving parts than a ballpoint pen. You can make a lethal (though inefficient and awkward) gun in the plumbing department of Home Depot. Any competent machine shop or home hobby machinist can make a basic gun with tools they already own. Even a more sophisticated automatic or semi-automatic gun can be made with relative ease; it's only things like superb accuracy or high reliability that are harder to engineer. Which means that guns ARE NOT GOING AWAY, EVER. They may be harder to buy legally, but we've seen how well that keeps people from drugs. Add to that the fact that if you're hellbent on killing folks, there are other ways to do it. Pipe bombs, poison koolaid, even just plowing a truck through a crowd... there will never be a shortage of ways to kill people.