A federal court has stayed California's new law requiring the surrender/transfer/sale of "high capacity" magazines (more than 10 rounds). The court's decision issuing the injunction is here:
http://www.courthousenews.com/wp-content/uploads/2017/06/Calif.Guns_.pdf.
You've gotta love the first line: "On July 1, 2017, any previously law-abiding person in California who still possesses a firearm magazine capable of holding more than 10 rounds will begin their new life of crime."