From Reason:

But not according to the state of California, where Linton and Stewart have long led law-abiding lives. The California Department of Justice (DOJ) maintains that their vacated felony convictions forever disqualify them from buying or possessing guns. Last week Linton and Stewart, joined by the Firearms Policy Coalition and three other gun rights groups, filed a federal lawsuit in San Francisco, arguing that California’s policy violates the Second Amendment, the Full Faith and Credit Clause, and the Privileges and Immunities Clause.

California law, like federal law, prohibits people with felony convictions from owning firearms. On its face, that provision does not apply to people like Linton and Stewart, since their felony records have been vacated and therefore no longer exist as far the courts of conviction are concerned. Yet the California DOJ has told them that the state does not recognize those legal facts.