The Calguns Foundation, the Firearms Policy Coalition, the Firearms Policy Foundation and the Second Amendment Foundation teamed up to file a lawsuit against California over the current 10 round limit. The most current law prohibits grandfathered magazines, and that is the law challenged.
http://www.guns.com/2017/04/29/gun-owners-sue-california-over-large-capacity-magazine-ban/
From: Guns.com
