Hops, I'll take exception to your statement that the purpose of government is to guarantee certain rights, including the right to keep and bear arms. That amendment doesn't charge the govt. to protect our right, but instead forbids the govt. from taking any action that infringes the right. The right we have under the Second Amendment is the right to protect ourselves with arms from the government's infringement of OTHER rights enumerated in the Constitution.. The people had very little trust in governments of any kind and the Bill of Rights was a reassurance to the people of the several states that the government would not be able to impose the thinking of Bostonians and New Yorkers or Philadelphians on the people of Virginia, Georgia,, Maine, etc., on all the people of the other States. They were (rightfully) distrustful of any government because they had experienced being treated as second-class citizens (subjects) of England's Parliament.
I could argue with other statements made in this string about civilians rebelling against the Army's might, but I'll only say that our Army is not as likely as it once was to fire upon Americans (Google the Army's firing on strikers at Ford's factory, for example) as it once was. The Nuremburg trials pretty much did away with the defense of "I was only following orders". When I took the oath as a soldier it was something about following the LAWFUL order of my superiors.