SALEM — Oregon gun-safety advocates are working to collect signatures to put an initiative on November’s ballot that would require people to get a permit to buy a gun and would stop the sale of gun magazines that hold more than 10 rounds.

Initiative Petition 17 also would close the so-called Charleston loophole by requiring people to pass a background check before buying a gun.

Under current federal law, firearms dealers can sell guns without a completed background check if the check takes longer than three business days. That’s how the gunman in the 2015 Charleston, South Carolina, mass shooting at a Black church bought his gun and killed nine people.

It’s unclear in Oregon how many people have been able to buy guns as result of delayed background checks. The Oregon State Police’s Firearms Instant Check System, which tracks when a gun sale is denied and why, hasn’t updated its data since Jan. 31, 2021.

There would be exceptions under the initiative for high-capacity magazines made for military and law enforcement. Those who already own such large-capacity magazines could keep them but not sell or transfer them to anyone.

Permits to buy a gun would be good for five years and be renewable.

Penny Okamoto, executive director of Ceasefire, said Initiative Petition 17 would accomplish several important goals of gun control advocates.

“We’ve got too many guns in the wrong hands, and there’s too many bullets,” she said.

The campaign aims to obtain 140,000 signatures for the petition by July 8.

The gun-control advocates are focusing on Initiative Petition 17, and don’t plan to collect signatures at this point for a second gun measure, Initiative Petition 18, which they will work to have introduced in the Legislature next year.

Supporters have called for similar gun-regulation measures for years. But they say the explosion of gun violence in Portland since 2020, and the latest mass shootings add to the urgency.

In Uvalde, Texas, an 18-year-old man fatally shot 21 people including 19 children at an elementary school. Ten days earlier, a gunman shot and killed 10 people, almost all of them Black, at a grocery store in Buffalo, New York. An 18-year-old white man is charged in the shooting. And a day later, a 68-year-old Asian man in Laguna Woods, California, is accused of opening fire on a Taiwanese congregation the next day, killing one and injuring five others.

Portland recorded its highest number of homicides in 2021, with 92, and is on pace to surpass that peak this year. Thirty-eight people have died in homicides since January, most from shootings.

Oregon has seen four mass shootings so far this year — three in Portland and one in Eugene — defined as four or more people shot, according to Ceasefire Oregon. Since 2014, Oregon has had 20 mass shootings, of which 12 have occurred since Dec. 31, 2020, the group said.

The Lift Every Voice Oregon campaign started shortly after the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, where 17 students and staff were killed and 17 others injured. The group ran out of time to obtain sufficient signatures for similar petitions that year. Bills reflecting the initiatives never got a hearing in the state Legislature in 2019, and in 2020 and last year, the COVID-19 pandemic hampered signature-gathering efforts.

The Rev. W. J. Mark Knutson, of Augustana Lutheran Church, Portland, is one of the chief petitioners for the initiatives and helped start the associated campaign and political action committee, Lift Every Voice Oregon.

Knutson gathered recently with the two other chief petitioners, Rabbi Michael Z. Cahana, of Congregation Beth Israel, and vocalist Marilyn Keller, who is in the Jazz Society of Oregon Hall of Fame, and other supporters.

“We can’t just sit by with thoughts and prayers and weep,” Knutson said. “We have to see some action.”

“We can do this if we can get enough help in the next six weeks,” Knutson said, noting that teenagers to an adult in his 90s have been volunteering to obtain signatures.

Liz McKanna, who is involved in the Lift Every Voice Oregon campaign, said the group decided to focus on Initiative 17 this year because it addresses a broader class of guns and “will do more right away to reduce the injuries and deaths from gun violence.”

David Wheeler, also involved in the campaign, said requiring a permit and safety class completion to buy a gun is common sense, considering new drivers are required to obtain permits and licenses to get behind the wheel of a vehicle.

“We’re going to be strategic about how to use our resources,” Cahana said, adding that Initiative 18 will remain part of the group’s long-term approach.