Your interpretation is nicely aligned with Justice Scalia's interpretation which is based on "originalism". If you haven't done it yet, you would no doubt like to read The Heller Opinion in regard to the extensive discussion of the prefatory clause. I certainly am not one to champion the originalist, nor the strict constructionist, approach to modern law. I believe if a Justice is rigid in adhering to either of this two principles in reading the law, and in particular two-hundred-year-old law written at a time when nothing moved faster than a horse, that they will freeze our Constitution in time and by so doing cause its unnecessary obsolescence. Fortunately, originalist Scalia wasn't consistent. He was the originalist when it suited his purpose and he had nothing better to fall back on. This trait must have exasperated his colleagues, but thankfully he wasn't rigid in applying his, as it turned out, rather 'flexible' principles. In his time on the court, he was by far our most colorful judge.