If you honestly think the US will ever enforce any sort of gun control, let alone a gun ban, you're completely off your rocker. First of all, who would confiscate all the guns already in circulation? Having a police force going around taking peoples guns would be a bloodbath for both sides, and many military personnel have their own private collection of firearms so good luck having them seize the populations weapons.
But lets say that by some miracle every gun in the US magically disappears, know what happens? Yes gun crimes go down, but every other violent crime starts to sky rocket, with more and more people getting stabbed with knives or beaten to death with blunt weapons (And look! People are still getting shot with illegally acquired firearms anyway!). And if people really wanted to kill as many people as they could all they have to do is build a bomb, do you know how easy that is? A quick google search brings up everything I need to make the same type of bomb the Boston Bombers used. $150 and a quick trip to Walmart and I have everything I need, all I have to is leave a gym bag in the middle of a school gymnasium during an assembly and there you go, massive casualties, no guns required.
Guns are not the problem in the US, it's just a sad fact of life that most of these people use them (often acquired illegally) to preform their heinous acts. You wanna solve this issue? Stop putting the blame on guns and invest in some mental health programs.