I assume you're talking about United States v. Miller. If you are, you're wrong in what you're saying. The USSC in Miller determined that there is a second amendment (of course there is); however, they did not overturn the gun law as a violation of the second amendment. (They ruled in favor of the US). Like I said, from my knowledge the USSC has never overturned a gun law on second amendment grounds. Wrong. They remanded it back to the lower court as they could find no militia purpose for a sawed off shotgun. Miller died before it could be re-heard at the lower court, so the judges made it up on the fly from the prosecuters arguments.
As I said. Do try to keep up.