Personally, when discussing 2nd A issues, I always summarize the Constitution as being about power: who has power over what functions of gov't and what the limits of those powers are.
I then point out that the Amendments are about the limits of those powers in regards to the citizens and what powers the citizens can hold. I then point out that in this context, the 2nd amendment was never about hunting or sports; it's about power. Ultimately, Mao was right; power does come from the barrel of a gun.
It might be a bit uncomfortable to think that the Constitution has built in a citizen-operated 'kill switch' in case of bad governance, but it's also comforting to think that the smartest guys in the room back in 1787 also thought that they might not be smart enough to have made a constitution that would effectively check/balance the rise to tyrannical power of the Federal government.
I'm right about the metric system 3/4 of the time.