there is sometimes a necessity for killing; when dealing with corrupt or subverted politicians, or religious terrorists screaming "convert or die", or when socialists try to take away your right to self-defense, or when a criminal attacks you in the street.

self-defense against any of the contingencies is the first right, and really the only one that matters, for without, how will you defend your other rights?

guns are the most efficient means of self-defense, both individually and for societies as a whole