Any realistic assessment of the current political landscape in the U.S. can only lead to the conclusion that no serious gun control effort can be passed in this country. We now have two mass gun slaughters of elementary kids under our belts and if they can't cause a big enough backlash to do it, nothing will. And even if we somehow do get our act together and pass some strict new limits on firearms, the current hyper-partisan 6-3 wingnut Supreme Court is virtually certain to strike whatever it is down.
And yet, things can change. Really quickly too. Things that are unthinkable at one point, have later happened. There was once an anti-alcohol movement in this country powerful enough to get a ban on alcohol through Congress, and then to get the state legislatures in 46 states to ratify it. I can't imagine it passing even one state now (not even Utah). And then, just 14 years later, it changed again. Congress passed a repeal of the alcohol ban, and 38 state ratified it (even Utah).
Amending the U.S. Constitution is really hard, harder than just passing regular gun control legislation and packing the Court. But even either of those things can be done, and the right movement can catch fire at just the right time and do it. The story isn't done being written yet. Even a long-shot is worth trying if it will save lives.