As a retired airline pilot, gun owner and gun-control activist, Bob Mokos has witnessed the public outcry for changes to the nation’s gun laws many times, only to see the momentum later fade from public consciousness. It happened after Newtown and Orlando and Texas and Las Vegas.

But as he stood outside the Senate and House chambers inside the State Capitol last week, where hundreds of his fellow advocates wearing red T-shirts chanted “Save our kids” and shoved fliers into the hands of lawmakers, Mokos said he couldn’t help but feel this time was different. Something about the tragedy in Parkland, Fla., where a 19-year-old gunman shot and killed 17 people — most of them students — at his former high school, resonated in a way that Mokos hadn’t felt before.

“Look at all these people,” he marveled as he peered over the hundreds gathered at the Capitol. “I sense the groundswell is growing … If this is not the tipping point, we’re getting awfully close.”

Amid the surging grass-roots outrage in the aftermath of the nation’s latest mass shooting, Mokos and a growing cohort of gun-control activists are cautiously optimistic that this time, their voices will make a difference. With angry teenagers planning walkouts in high schools across the country as well as President Donald Trump issuing a tweet calling for some changes, including “Comprehensive Background Checks with an emphasis on Mental Health,” many are galvanized by what seems like a shifting momentum.

Even so, Mokos and others know new regulations won’t come easily on an issue so bitterly divisive.

While the National Rifle Association was quiet in the first days after the Parkland shooting, executive vice president Wayne LaPierre eventually spoke out, saying, “We share a goal of safe schools, safe neighborhoods and a safe country.” But he criticized gun-control advocates, arguing that they are trying to “eliminate the Second Amendment and our firearms freedoms so they can eradicate all individual freedoms. What they want are more restrictions on the law-abiding.”

Gun-rights activists have cautioned against hastily passing new restrictions and even promoted other proposals to expand gun freedoms.

“There’s always frustration,” Mokos said. “Somebody’s got to push this thing to the next level.”

For Mokos, 68, the push to add gun regulations has been something of a personal mission, fueled by the wave of mass shootings over the past two decades and rooted in the brutal murder of his sister, who was killed by a firearm in a robbery more than 30 years ago.

As he has done since becoming an activist on the issue two years ago, Mokos has tried to mobilize others in the wake of the Parkland shootings. He made his plea and told his personal story in a speech to a Rotary group in Eagan, spoke face-to-face with politicians at the Capitol in St. Paul, and helped establish a chapter of Moms Demand Action in Duluth.

Along the way, he almost always carries a large photograph of his sister when he goes to events, tearing up when he talks about her. Diane Mokos Kriz, a nurse midwife at Cook County Hospital in Chicago, was killed outside a religious building when a gunman shot her at point-blank range in the temple, Mokos said. She died instantly, leaving four children behind. The crime remains unsolved.

The murder shocked the whole family, Mokos said. At the time, it raised his awareness of crime in general, not guns specifically.

Guns had long been part of his life; he was a champion shooter on an NRA-sponsored Boys Club rifle team as a teenager in the ’60s. He was surrounded by guns during his stint in the Air Force. After the Sept. 11, 2001, terrorist attacks, he applied to become a federal flight deck officer so he could carry a weapon in the cockpit.

His gun epiphany came, he said, after the December 2012 massacre at Sandy Hook Elementary School, where 20 children and six adults were shot and killed by a 20-year-old gunman.

“I bawled,” Mokos said.

Months later, when he saw legislation to strengthen background checks for prospective gun owners fail in Congress, “I was furious.”

At that point, he started looking for a gun-control group to join, eventually settling on the nonprofit organization Everytown for Gun Safety, he explained, because it offered him a platform to tell his story.

Speaking before groups, one of the first things people learn about Mokos is that he himself is a handgun owner.

“I am not against the Second Amendment,” he said at a Rotary Club lunch last week. But, he said, he is against “the easy access and the number of guns that are out there.”

Mokos has had plenty of practice talking about guns to people who don’t see things the way he does. In a way, he’s surrounded by them.

After years of flying 747s, many of his former co-workers are gun-rights advocates, he said, noting that “the culture in the cockpit is very conservative.” Some of his relatives own guns, too, including a close family member who shoots an AR-15 as a hobby.

When he talks to other gun owners one-on-one, Mokos said, most agree that something needs to be done to curb mass shootings and other gun violence in the country. The debate is what.

Mokos tries to meet other gun owners on common ground. He often starts by talking about background checks, which polls consistently show a vast majority of Americans favor. In Minnesota, checks are mandatory for someone buying a gun from a licensed firearm dealer, but Mokos favors legislation to extend the requirement to private transactions and online sales.

“Everybody agrees on criminal background checks. Why don’t we have them?” he asks in frustration.

But he knows opponents argue that that could amount to a registry.

Mitchell Hamline School of Law professor emeritus Joseph Olson, who founded the Gun Owners Civil Rights Alliance in Minnesota, called registries “the thing that gun owners quite rationally fear most” because they consider it an essential link toward confiscation.

“The only reason for having it is, ‘We want to know how many you have so that when we come to your house we can get them all,’ ” Olson said.

Most mass shooters have legally purchased their guns, passing background checks, anyway, Olson said. Before Minnesota does anything, Olson said, the federal database used in background checks has to be improved. The transfers in private sales in Minnesota, he said, have not proven dangerous.

“The idea that [the state’s] responsible gun owners are engaging in transactions designed to transfer guns to bad people is simply false,” he said.

After discussing background checks, Mokos said conversations with gun owners often move on to debates over assault weapons, bump stocks and conceal-and-carry laws.

At some points, however, Mokos knows he and his friends and family will agree to disagree.

“They’re family and we love ’em dearly,” he said. “We’ve just got to keep working on them.”

A couple of Mokos’ siblings have followed in his footsteps, joining gun-control groups and speaking out in honor of Diane.

Some other close family members who own guns say they consider his efforts “noble.” They see how he’s been personally affected and believe he’s trying to do the right thing.

The relative who owns the AR-15, who didn’t want to be identified because disclosing his name could tip gun thieves to where he lives and the whereabouts of his rifle, said he agrees something needs to be done, but he’s just not sure what.

“If they can come up with legislation that is going to prevent these actual weapons from getting in the hands of people who will do harm with them and that will actually save lives, then I’m OK with that,” he said. “But the question is, they don’t just ever stop there. There’s always bills thrown into the legislation that will make it more restrictive.”

The relative said that Mokos’ main concern in their discussions has been that he keep the gun out of the hands of children or anyone else who shouldn’t have access to it — a responsibility he said he takes very seriously.

“I support [Mokos’] cause to try to protect lives … but I would really like also to have my rights personally protected on my ability to carry on my hobby and defend myself.”

Mokos said he plans to shoot an AR-15 in an effort to better understand how it works and why it’s attractive to some gun enthusiasts.

“There is no one cure for everything,” Mokos acknowledged last week to a Rotary Club audience member, who stood up at the luncheon and asked Mokos how many mass shooters used legally purchased weapons vs. illegally purchased ones.

The audience member, a gun owner with a small child at home, said afterward that he’s been giving the gun-control issue much thought of late, but wondered if it is “treating the symptoms rather than the cause.”

Mental health, violent images and other issues all need to be addressed along with guns, Mokos said.

“We can have the Second Amendment … we have to balance that with the easy access,” he said near the end of his speech.

Moments later, he concluded: “I hope I didn’t step on anybody’s toes, but it’s a very emotional issue to me.”