Stevens pointed out in his dissent that:
The key to that decision did not, as the Court belatedly suggests, ante, at 49–51, turn on the difference between muskets and sawed-off shotguns; it turned, rather, on the basic difference between the military and nonmilitary use and possession of guns. Indeed, if the Second Amendment were not limited in its coverage to military uses of weapons, why should the Court in Miller have suggested that some weapons but not others were eligible for Second Amendment protection? If use for self-defense were the relevant standard, why did the Court not inquire into the suitability of a particular weapon for self-defense purposes?
Of course, if it can be demonstrated that new evidence or arguments were genuinely not available to an earlier Court, that fact should be given special weight as the Supreme Court considers whether to overrule a prior case. But the Heller Court did not make that claim that new evidence or argument was available, because it Could not. Instead, it chose to allege that the Miller decision was "unclear" and did not offer proper guidance--despite nearly 70 years of precedent to the contrary.
Although it is true that the drafting history of the Amendment was not discussed in the Government’s brief in Miller, it was not the drafting history that the Miller Court’s decision depended. Those sources upon which the Heller Court relied most heavily were available to the Miller Court. The Government cited the English Bill of Rights and quoted a lengthy passage from Aymette detailing the history leading to the English guarantee, Brief for United States in United States v. Miller, O. T. 1938, No. 696, pp 12–13; it also cited Blackstone, id., at 9, n. 2, Cooley, id., at 12, 15, and Story, id., at 15. The Heller Court was reduced to critiquing the number of pages the Government devoted to exploring the English legal sources. Only two (in a brief 21 pages in length)! Would the Heller Court be satisfied with four pages? Ten pages?
In short, there was no significant change in the law, new evidence, or arguments other than a couple of decisions which decided to follow "recent scholarship" of dubious quality that lead to certiorari in these cases.