The probability is higher that an aggressive, unstable person will use a gun against someone, than for a normal person to actually need a gun for self-defence.
The major viable reason to have a gun at this point in time is because you enjoy guns, need them for some recreational activity or for hunting. These would not be affected by restricting (not banning) the right to bare arms, considering you are a sane, non-criminal member of society.
If you really feel as though having a gun will save your life and your families lives, you shouldn't opposed to going through some extra loops to get a gun. If you are truly fit to own a gun (you know how to use it and you are mentally stable) then gun control laws should not restrict your access.
Some people have been determined by society to be incapable of being trustworthy with such responsibility. We deny driving licenses and voting rights for such reasons - it makes sense to deny some people the ability to put bullets into people.
People living in Alaska should be able to have bigger guns because there are bigger threats such as wildlife attacks there, while people living in suburban America don't need to have assault weapons because they would never need something like that
Perhaps the right to bear LETHAL arms should be restricted. If guns couldn't kill people, there would no longer be the need for a cliché and sportsman or collectors could still hoard firearms to their hearts' content while the less innocent would have to settle for a more personal engagement.
The only way by which firearms can be restricted are if other people with firearms prevent people from obtaining said firearms, meaning firearm ownership will only be reserved for a privileged class.
If someone comes into my house with a knife with the intent to stab me and chop me up into pieces, I want to be able to reach for a gun and shoot them because I don't know if I could disarm a knife-wielding person.
The gun problem is so endemically infested into the core of American culture that it isn't going to go away - The best solution is more responsible people with firearms because criminals aren't going to give theirs up because the gov't said they should.
Our nation was founded on the notion that every person has the self-evident right to live. And the Constitution directs the government to provide for the general welfare. Tacitly allowing mass shootings through willful inaction does not provide for the general welfare.
sources:
The Declaration of Independence and the Constitution of the United States
The saying "guns don't kill, people do" is cliche, but raises a valid point: guns facilitate killing, but do not cause it or carry it out. In fact, gun bans are consistently linked to higher murder and homicide rates. Banning guns just means that only police and criminals will have them.