The new initiative, which could be part of an unusually long roster of propositions considered in November, will require more than 360,000 signatures to make the ballot. It’s been characterized as “cobbled together” from bills that faltered in the state legislature, and the Sacramento Bee has a helpful summary of what it calls for:

It would ban the possession of large-capacity magazines—more than 10 rounds—and require anyone who currently has them to sell to a licensed firearm dealer, transfer them out of state or relinquish them to law enforcement to be disposed of. The pending measure also would force those selling ammunition to be licensed like firearm dealers and require the purchasers to go through a background check. [Ed. note: California would be the only state in the nation to mandate background checks for those buying ammunition “at the point of sale.”] It would establish a process to recover guns from people prohibited from owning them because of their criminal record; mandate individuals whose guns were lost or stolen to report to law enforcement; and compel the state Department of Justice to notify the federal government when someone is added to the database of people barred from buying or owning a firearm.

The provision focusing on high-capacity magazines seems designed to prevent another mass shooting in California. These implements are characteristic of mass shootings: They may’ve been used in the San Bernardino shooting; a New York Times report describes the two shooters’ weaponry as “.223-caliber assault rifles and semiautomatic handguns.” And high-capacity magazines were used by Adam Lanza, the Sandy Hook shooter; James Holmes, who opened fire in an Aurora, Colorado, movie theater; and Seung-Hui Cho, the Virginia Tech shooter, among others.

States with stricter gun-control laws on the books have “significantly lower” gun deaths, per a 2011 Atlantic analysis. But whether that’s a causal or correlative link, and whether mass shootings can be wholly prevented by tough gun laws isn’t clear-cut. Gun laws may inhibit mass shooters the way they inhibit others who shouldn’t have access to a gun, such as those with felony convictions or who have been adjudicated to be dangerous to themselves or others. (Though it’s worth noting that loopholes in those laws allow many people to slip through the cracks.) California, too, has laws on the books that ban felons and those deemed dangerous from possessing guns. California’s laws also prohibit ownership by those who’ve been convicted multiple times of dangerously brandishing or otherwise “unlawfully” using a gun; who’ve been found not guilty of a violent felony by reason of insanity; who are “gravely disabled” by mental illness or seriously affected by alcoholism; and those who are “mentally disordered sex offender[s].” But some of the risk factors most commonly associated with potential mass shooters are less susceptible to regulation.