The Second Amendment did not limit the type of arms it applied to, and the reason that it's preamble referred to the dependency of the security of a free state on a well-regulated militia was because it was in the context of the best universal opinion at the time that large standing professional armed forces for either internal security or international conflict were a mechanism of tyranny, and that having a free country absolutely required a dependency on avoiding those and instead relying on mobilizing the armed populace (with all the weapons of war) to deal with internal and external threats.
Leaving aside gun laws, we've long since completely abandoned the premise of the second amendment on a far more fundamental level with our professional militaries and paramilitary police forces.
Only because Miller was not properly heard almost 100years ago.
Short barrel shotguns were extremely common in world war 1 trench warfare, and that’s what Miller was charged with. Too bad he was dead before the supreme court heard that case.
Leaving aside gun laws, we've long since completely abandoned the premise of the second amendment on a far more fundamental level with our professional militaries and paramilitary police forces.