SALEM -- Gun rights activists troubled by surging legislation meant to expand background checks for gun sales have filed recall petitions against three Oregon lawmakers. And they warn more could be on the way.

On Wednesday, a Hillsboro man submitted paperwork against Sen. Chuck Riley, D-Hillsboro, and Rep. Susan McLain, D-Forest Grove -- both of whom are in their first terms and part of an expanded Democratic majority enabled, in part, by campaign donations from gun-control advocates.

Riley, who narrowly defeated Republican incumbent Bruce Starr, was particularly helped by money from a gun-control committee led by former New York Mayor Michael Bloomberg. His vote was key to helping Senate Bill 941 pass to the House on a 17-13 vote this week. Both McLain and Riley sponsored the bill.

On Tuesday, the day of the Senate vote, a Junction City gun shop owner submitted paperwork against House Majority Leader Val Hoyle, D-Eugene. Hoyle, who has courted gun rights advocates, had told The Oregonian/OregonLive she expected SB 941 to move quickly through her chamber. The Oregonian/OregonLive obtained all three petitions Thursday through a public records request.

The actions appear connected, at least informally, and could spread. They follow a similar effort in Colorado in 2013 that saw two lawmakers lose their posts, including the state's senate president, over support of bills far more expansive than SB 941.

"We're not interwoven I would say," said Ben Busch, the constituent who filed against McLain and Riley, also invoking their stances on education funding. "We're aware of each others' actions and support each other where we can. There's probably more on the way. It wouldn't surprise me if we have more soon."

Busch also says he expects to receive financial help -- given that he'll be running twin recall efforts -- from groups he declined to identify. He said a website could be up by the end of this week.

"We have support from other groups," Busch said.

Riley's office, when asked for comment, issued a statement from the senator that called the petitions the work of "extreme right-wing groups" who "may not like the fact that I won":

"The voters of Senate District 15 know that I have always supported common sense legislation to promote gun safety. I proudly cast a "Yes" vote on SB 941 to close the loophole that allows felons, domestic abusers, and people with severe mental illness to get access to a gun. Common sense gun safety was a key issue in my campaign and I'm delivering on my promises to the voters. Extreme right-wing groups may not like the fact that I won, but I am doing exactly what I said I would do. I respect the right of citizens to exercise their beliefs in the democratic process. I am also confident that the vast majority of people in my district support gun safety, and that my vote for SB 941 is democracy in action."

McLain's office deferred to Hoyle's office, which issued a statement from McLain:

"I ran for office to invest in our classrooms and to work on policies that protect the health and safety of our community. Since taking office in January, I've had the opportunity to work and vote on numerous bills that will improve the lives of all Oregonians. I'm proud of everything we've accomplished since the start of the session.

Unfortunately, a fringe group has started a recall effort against me over my support of a bill that will close the background checks loophole for private gun sales. I believe that this bill will save lives by ensuring that this gaping loophole isn't used to put guns into the hands of criminals, domestic abusers, and people with severe mental illness.

I fully support the 2nd Amendment, and I believe that this is a common sense policy that will make our community safer while still protecting the rights of gun owners. Our community agrees: A recent poll shows that 87 percent of Oregonians support closing this loophole, including 83 percent of gun owners.

I look forward to continuing to work with and on behalf of everyone in House District 29, and I remain focused on doing the important work of the legislature."

Hoyle also defended her support of SB 941 -- which tightens extends background checks to private gun sales -- as "common sense."

"I want to be clear that I won't be intimidated away from doing what I think is right," she said. "The recall is an important part of the democratic process and it's his constitutional right to file the petition. But it's important to note that I was reelected by a 12-point margin. I'm confident that I have the support of the majority of the people in my district."

Messages left for Kevin Starrett of the Oregon Firearms Federation also were not returned. A website run by gun advocates shows discussion over the issue, and going after Riley, was in play at least as early as March. Another discussion page on that site, Northwest Firearms, contends the activists pushing to recall Riley are "coordinating" with the firearms group.

In Oregon, it's been rare for a recall threat to actually hit the ballot. To make a likely August ballot, the recall petitioners now have 90 days to collect enough valid signatures to match 15 percent of the total votes cast for governor last year in each of the elected official's districts. That number includes write-in votes.

Officials facing recall, assuming suffiicient signatures are turned in, then have five days to resign or file a statement in their defense. The election would then be held after an additional 35 days.

Busch says Riley was chosen because of how close his victory was last fall. Riley was helped not only by the Bloomberg money but also by the presence of a libertarian candidate.

"If we went after [Sen. Floyd] Prozanski[, D-Eugene,] or [Sen. Ginny] Burdick[, D-Portland," Busch said, "it would have been a more difficult challenge."

Since taking office, Riley has supported efforts to limit how much money Washington County receives from the state's Gain Share program. Busch says that issue has sparked interest from Riley foes who aren't particularly exercised by the gun debate. Expanding their effort to wrap in outcry over other issues was among the tactical points advocates traded in March.

"It's a conversation we're following up on," Busch said.

Meanwhile, a spokeswoman for the Bloomberg-backed committee that helped elect Riley and push hard for SB 641 this session, Everytown for Gun Safety, said the recall efforts amounted to "the dirty tricks of the gun lobby." She also pointed to what happened in Colorado after the lower-turnout 2013 elections that seemed to loom as a setback for the movement.

"We won back the seats," Erika Soto Lamb said, noting Everytown not only donated to the candidates who lost their seats but also to the candidates who reclaimed them.

One of the seats was filled by a former staffer for one of Everytown's predecessor organizations, Mayors Against Illegal Guns. And just his week, she said, efforts to repeal Colorado's background checks and ammunition limits failed.

"This is not unfamiliar for us," she said.

-- Denis C. Theriault

503-221-8430; @TheriaultPDX