Newsom is pushing for background checks for the purchase of ammunition. (Photo: File)

Newsom is pushing for background checks for the purchase of ammunition. (Photo: File)

California Lt. Gov. Gavin Newsom and a group of activists announced their intention Thursday to put a tough firearms-control measure on California's ballot next year aimed at requiring background checks for ammunition purchases and forcing gun owners to give up large-capacity magazines.

Newsom's measure would require owners to turn the outlawed magazines into police for destruction, sell them to a licensed firearms dealer or move them out of the state -- just as San Francisco supervisors and Sunnyvale voters chose to require in 2013. New York, New Jersey, Hawaii and the District of Columbia also have such laws.

The measure also would require licensing of ammunition sellers and instantaneous point-of-sale background checks for all ammunition purchases to weed out those convicted of a felony or a violent misdemeanor, those with restraining orders against them or those declared dangerously mentally ill.

No other state requires background checks for ammunition purchases, the San Jose Mercury News reports.

The measure would also require firearm owners to notify law enforcement if their firearm has been lost or stolen. Eleven states and the city of Sacramento already require this, but Gov. Jerry Brown vetoed bills to do just that in 2012 and 2013.

Newsom and gun-control groups will need signatures from 365,880 registered voters to place the initiative on the November 2016 ballot, which will likely be full of other controversial and costly measures, including proposals to legalize recreational marijuana, raise the tobacco tax and overturn the state's ban on single-use plastic grocery bags.