Proposition 63 would tighten a set of sensible gun-control laws recently signed by Gov. Jerry Brown and enact others that state legislators have failed to pass.

“This closes all kinds of loopholes,” said Lt. Gov. Gavin Newsom, a chief promoter of the initiative.

The most controversial element of the measure is its toughening of the requirements on buyers and sellers of ammunition. As Newsom pointedly noted in an editorial board meeting, “A gun isn’t inherently dangerous.” It takes a bullet to make one lethal.

Under Prop. 63, buyers of ammunition would be subjected to background checks similar to those required of gun purchasers. Sellers would need to be licensed. No longer would Californians be able to buy ammunition online and have it delivered to their homes; they would need to pick it up at a licensed dealer, as they would a firearm.

The California Legislature recently tried to preempt Prop. 63 by passing a decidedly weaker law (SB1235) on ammunition sales. Prop. 63 provides for more rigorous background checks and fewer exemptions for both buyers and sellers. It requires licensed vendors to report lost or stolen ammunition.

Moreover, gun owners would be required under Prop. 63 to report lost or stolen firearms.

The proposition would close one problem that has arisen with Prop. 47, passed by voters in November 2014. It raised the threshold for felony theft to $950; thus, a criminal who stole a gun of lesser value could be charged only with a misdemeanor. Prop. 63 would elevate any gun theft to a felony, which would criminalize the possession of firearms by those convicted.

Another key provision of Prop. 63 would create a system for more readily confiscating guns from felons who are proscribed from possessing them after their conviction. The “honor system” has not been working. State Attorney General Kamala Harris has been making a concerted effort to seize guns from those on the prohibited list, but it’s a big job — and a dangerous job — for her Department of Justice. In 2014, state records showed that 17,000 people on that list still had more than 34,000 firearms, including 1,400 assault weapons.

The gun-rights lobby has been trying to alarm law-abiding owners with horror stories about how Prop. 63 would criminalize bullet sharing among hunters and other shooting partners. Not true. The initiative is clear that it is illegal only if the individual sharing bullets does so with someone “he or she knows or using reasonable care should know” is banned from possessing ammunition.

The restrictions in Prop. 63 are sensible, practical, respectful of the Second Amendment rights of law-abiding Californians, and in the interest of public safety.

Vote yes on 63.

What Prop. 63 does

Imposes background checks through the state Department of Justice for the purchase of ammunition.

Requires a state license to sell ammunition.

Prohibits possession of large-capacity ammunition magazines.

Requires the reporting of lost or stolen guns or ammunition to law enforcement.

Ensures that anyone convicted of a gun theft is ineligible to purchase or possess a firearm.

Sets up a system to document that felons sell or transfer their firearms soon after conviction.