The District of Columbia's ban on firearm magazines that hold over ten rounds was the subject of oral argument in the D.C. Circuit on February 13. The case is Hanson v. District of Columbia, and the appeal concerns the district court's denial of a preliminary injunction against enforcement of the ban. The circuit panel included Judges Patricia Millett ('13) and Justin Walker ('20), and Senior Judge Douglas Ginsburg ('86).
The argument should have turned on one, and only one, question: are the banned magazines commonly possessed by law-abiding citizens for lawful purposes? As Professor Mark W. Smith has explained, under District of Columbia v. Heller (2008) and N.Y. State Rifle & Pistol Ass'n v. Bruen (2022), that is the only relevant question in an arms ban case. See Smith, "What Part of 'In Common Use' Don't You Understand?" Harvard JLPP (2023). That is because the common use test is the product of the text first and then history approach the Supreme Court has applied in this context. In Heller, the Court examined the Second Amendment's language to determine that as a matter of plain text "arms" includes (but is not limited to) all firearms. It then examined history to determine that only dangerous and unusual firearms can be banned. It follows that citizens have a fundamental right to possess firearms that are in common use today, because if they are in common use, they cannot be "dangerous and unusual."
The answer to the common use question in this case is a resounding and unequivocal yes — there are hundreds of millions such magazines lawfully owned for lawful purposes by Americans today. By any measure, that's common possession. To be sure, magazines are not themselves firearms, but they are key components of all modern semiautomatic firearms, as they are the part of the firearm that holds and feeds the ammunition. And the practical effect of the magazine ban is to prohibit an entire category of firearms; i.e., firearms that are capable of firing more than 11 rounds (one in the chamber, 10 in the magazine) without reloading.
