I'm assuming you're talking about the ban on magazines capable of holding more than 10-rounds. If the magazines were owned by you in California prior to January 1, 2000 then you can take them in and out of California legally. If you own legal magazines you can sell them to a person not in California, but you can't sell them to a California resident (unless the person is licensed under 12071 or is a cop or something). You COULD break down the magazine into a rebuild kit and sell that to a friend, but it would be unlawful for him to assemble it unless he was rebuilding a magazine that he legally owned.