2016 California Proposition 63

The 2016 Proposition 63, titled Firearms and Ammunition Sales, is a California ballot proposition that passed on the November 8, 2016 ballot. It requires a background check and California Department of Justice authorization to purchase ammunition, prohibits possession of high-capacity ammunition magazines over ten rounds, levies fines for failing to report when guns are stolen or lost, establishes procedures for enforcing laws prohibiting firearm possession by specified persons, and requires California Department of Justice's participation in the federal National Instant Criminal Background Check System.

Supporters of the measure stated that it would "fix a major flaw" put in place by the passing of Proposition 47 in 2014 by stating that theft of a firearm is a felony, regardless of its monetary value.

A September 2016 poll from USC Dornsife / Los Angeles Times showed 64% percent of registered voters in favor of Proposition 63, 28% opposed, and 8% unknown. A November 2016 poll from Insights West showed 57% percent of likely voters in favor of Proposition 63, 35% opposed, and 8% undecided.

Proposition 63 passed, 63% to 37%.