[AngryParsley]

Magazine restrictions are a separate law in most states. California has an assault weapon ban which restricts features such a pistol grips, collapsible stocks, and flash hiders. They have another law restricting the possession of magazines with a capacity of more than 10 rounds. Old magazines are grandfathered in, so you can use them in legal rifles.

It looks like the law is similar in DC. Possession of a magazine with >10 round capacity is a crime. Other firearm laws are irrelevant to the case you linked to.

[sp332]

OK, interesting. I know my home state of NH also has an "assault weapons ban" that just bans certain magazines, although we probably have other laws too that one bugged me.