The NRA got into the position that they are in not because they are battling for the Second Amendment and the absolute right for Americans to own guns but because they are battling for the rights of the American gun manufacturers to sell unimpeded the guns that they manufacture. There is a difference. The NRA doesn't worry about the guns that are manufactured overseas or the guns that are banned the American gun manufacturers don't make. In fact, they are happy when these two categories of guns are banned or restricted because it means more gun sales for the American gun manufacturers.
To the NRA this isn't a question of constitutional rights, it is a mercantile one. They depend heavily on the support that they receive from the gun manufacturers. This is why it is so scary that they are now taking contributions from Russia, presumably made with the knowledge and at least the tacit approval of Putin, It would be difficult to argue that Putin and the other oligarchs that control Russia have a principled interest in the rights of private citizens to own guns. But they do have an interest in disrupting our democracy, in creating and increasing partisan divisions in the US and in disrupting the alliances of the Western democracies. And that is best accomplished by electing Donald Trump, which they have accomplished.