We already knew this ...

.
... but at least it's getting to be common knowledge:

Having just won their revolution, in which privately owned firearms played such a critical role, and mindful of the potential for their new government to potentially become tyrannical, the purpose of the Second Amendment was to make sure that the people of the United States would have the means to rise in revolt once again, should it become necessary.

That's what it's really about. It's not about hunting weapons; it's not about the "National Guard" (which isn't a militia). It's about everyday law-abiding citizens having the ability to resist a tyrannical government. And with that deterrent in place, we've managed 230 years without our government descending into tyranny (though it's come close).

And that's why Progressives hate it.

Yup ... nothing to do with controlling crime, that's just how they try to sell it to the public. Not that controlling crime is bad, it's just that gun control doesn't do anything to control crime.