Ok, let's try it this way.
You come to me and say that X won't let you have a handgun in your home for self-defense. I say that's wrong, X has to let you have it because X can't prohibit you from possessing an entire class of firearms which are commonly used in self-defense.
You come to me again and say that now A, B, C & D won't let you have a handgun in your home for self-defense. I say that's wrong, EVERYONE has to let you have it because such a prohibition violates a fundamental right. No one can prohibit you from possessing an entire class of firearms which are commonly used in self-defense.
How is the list of firearms that you can and can't own different after the second ruling than it was after the first ruling?
I presume "X" is DC after Heller and the other letters are the states after McDonald?
Please check out my post above, in which the salient phrase is bold and in red. The Heller opinion did NOT specify a standard of scrutiny. The McDonald decision DID specify a standard of scrutiny, in the "fundamental right" phrase.
Using the now-ubiquitous flash hider example, under the 14th, I could challenge the flash-hider ban because it limits my right to some firearms (rifles) with no compelling reason regarding public safety.