One of the best illustrations is the D.C. Circuits 2011 decision in
Heller v. District of Columbia (
Heller II). The decision addresses a challenge to the gun law devised by the District in response to the Supreme Courts 2008
Heller decision. Addressing a variety of challenges to the new law, the Court of Appeals applies the emerging dominant standard, asking 1) whether a restriction impinges upon a core right protected by the Second Amendment (with longstanding regulations presumptively lawful), and if it does, then 2) whether the restriction passes muster under the level of constitutional scrutiny the court deems appropriate.
One part of the challenged law banned a category of semiautomatic rifles, including the AR 15. Functionally this rifle is just like countless repeating rifles that have not raised the ire of legislatures. But based on its styling (it looks like the military M-16) it is perennially on the wish list of guns that should be banned. There are millions of AR-15s in the civilian inventory. This is one of the unintended consequences of the now expired 1994 Federal Assault Weapons Ban, which in the same breath banned the AR-15 (and a variety of other guns) and blessed functionally identical guns like the Ruger Mini 14 and cosmetically modified post-ban AR-15s (e.g., the same guns minus the superfluous flash suppressors, adjustable stocks and bayonet lugs).
Both the majority and the dissent acknowledge that the AR-15 is a gun in common use. How they proceed from there is illuminating. The dissent treats common use as a solid liberty-protecting standard. Guns in common use cannot be banned.
For the majority, acknowledging the AR-15 as a gun in common use is just a rhetorical lead-in to the burgeoning two stage standard of review. The court found that the D.C. law did in fact burden a core Second Amendment concern. But at stage two it determined that the ban does not substantially burden the right to self-defense (people could still have handguns and many other long guns).
Gun Rights in Scrutiny Land: The Federal Courts Attempt to Claw Back Heller - Fordham Law