From The Federalist:

However, as explained here, Heller erred in at least two respects. First, it misinterpreted the Supreme Court’s decision in U.S. v. Miller (1939). Miller indicated that the right to keep and bear arms includes all arms that “have some reasonable relationship to the preservation or efficiency of a well-regulated militia,” such as those that are “part of the ordinary military equipment” and any others the use of which “could contribute to the common defense.”

Miller also noted that militiamen were historically “expected to appear bearing arms supplied by themselves and of the kind in common use at the time,” so Heller ignored the discussion of military and militia arms and instead concluded that Miller limited the right to arms to those “in common use.”