Beyond that, I don't believe the Second Amendment was ever meant to be framed in that manner. The idea was that firearms helped keep the government from ruling over it's population by physical force rather than the consent of the governed. This, in simplest terms, would mean that what the government was allowed to use for force, so too should its citizens, thus carrying on the whole idea of checks and balances.
This was implicitly acknowledged in the Constitution's provisions for issuing letters of marque and reprisal.
A general point to make: widespread private ownership of weapons was so accepted, was in fact a key to our winning the Revolutionary War just a few years earlier, that the Second Amendment just acknowledges the fact and enforces it on everyone because the Anti-Federalists were wiser than the Federalists, they knew some hard red lines had to be drawn limiting the power of the new central government being created because any claims it would be self-limited were ludicrous. As we saw almost immediately, then through tyrants like Lincoln and FDR; Stalin wasn't the only national leader in the 1930s to deliberately starve people.
(3)The term “firearm” means (A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; (B) the frame or receiver of any such weapon; (C) any firearm muffler or firearm silencer; or (D) any destructive device.
This is basically any firearm. By this definition, any firearm not considered an antique is considered a weapon on mass destruction, which is clearly completely unworkable when considering allowing firearms for not just self-defense in the terms of attack but to the original reasoning of the second amendment which was to provide a check against a government ruling over its populace by force by allowing individuals to possess that same force.
You could try reading the decision, or Heller, but the go-to foundational book has long been That Every Man Be Armed: The Evolution of a Constitutional Right by Stephen P. Halbrook.
Our formal militia is vastly better regulated than the population bearing arms.