Grate read man ,I don't think the issue lies in the fact that people own a gun,It is the fact that people can own a arsenal of guns and weapons that are firing hundreds of rounds with out pause. IF I recall the gun laws in N.Z were changed after the Aramoana massacre on 13 November 1990.law then prohibited the ownership semi-automatic assault rifles and hand guns.
The Second Amendment of the United States Constitution reads: "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." This amendment was written in 1876 and I am pretty sure there were no semi-automatic assault rifles back then.