The key to understanding the 2A is knowing that it was drafted within the context of regulating a state militia. As the Supreme Court ruled in 1840, "A man in the pursuit of deer, elk, and buffalo might carry his rifle every day for forty years, and yet it would never be said of him that he had borne arms." Translation: owning a gun privately does not fit the definition of what it means to "bear arms."
So what does this mean for current gun debates? First, we need to remember that the interpretation that would read the 2A as a guarantee for private citizens' gun rights … is a very recent invention. It's not the traditional interpretation, so no conservative should be pretending that it is. Gun rights advocates should especially keep this in mind when they're tempted to charge gun-control advocates with revisionism. Second, we should stop pretending the right to "bear arms" has much, if anything, to do with individual freedoms. "Bearing arms" is a military term — admitting that does not in any way compromise my freedom as a private American citizen. Third (and this is not from the piece I'm linking to), we need to think about the relationship between freedom and life. Bill O'Reilly's recent rant — that Vegas is "the price" we have to pay for freedom — seems like it gets the relationship entirely wrong by subverting the order of goods. Our freedoms should only be guaranteed when they safeguard human life and flourishing. It shouldn't be the other way around (i.e. "Life is only worth pursuing when and only when US citizens' gun rights are safeguarded").
The Second Amendment isn't what anyone thinks it means. politico.com