The nation's most prominent gun control advocacy groups say they are better coordinating their work to challenge the gun industry and the powerful National Rifle Association (NRA).

The groups are riding high after the 2018 midterms, which saw Democrats retake the House and a number of candidates win election after touting tougher gun laws.

This week, advocacy groups will get another boost, with House Democrats poised to pass a bill mandating federal background checks for all firearm purchasers, the first vote on major gun legislation in years.

Groups including the Brady Campaign and Center to Prevent Gun Violence; Moms Demand Action for Gun Sense in America, the grass-roots arm of Everytown for Gun Safety; and Giffords, the group formed by former Rep. Gabrielle Giffords (D-Ariz.), have taken different approaches to push the issue. But in recent years they are increasingly marshaling their resources and coordinating to boost their influence.

The groups hold a weekly call to ensure they are working together to curb gun violence. They also frequently coordinate legal

efforts, such as last summer when the groups worked to block the publication of blueprints for 3D-printed guns.

"I think what's exciting about the fact that there are so many different groups is it really shows the wide appeal of gun violence prevention," Kyleanne Hunter, vice president for programs at the Brady Campaign, told The Hill.

The groups are also boosting their spending in hopes of leveling a playing field long dominated by the NRA and its

pro-gun rights allies.

In 2018, Everytown spent $30 million in support of candidates in the midterms and $1.35 million in lobbying expenditures. Giffords PAC spent nearly $7 million on candidates and $430,000 in lobbying expenditures. And the Brady PAC spent nearly $500,000, and the Brady Campaign nearly $120,000, in lobbying.

But while gun violence prevention groups see new momentum, the NRA still serves as a formidable rival, buoyed by its impressive fundraising and a membership the group says is more than 5 million, its highest ever.

The NRA spent over $862,000 for candidates in 2018 and over $5 million on lobbying.

The gun control coalition has also been working on broadening their base and electing more like-minded officials.

Shannon Watts founded Moms Demand Action in December 2012, the day after the Sandy Hook Elementary School shooting. In April 2014, it became part of Everytown for Gun Safety, which former New York City Mayor Michael Bloomberg helps fund.

"When I started Moms Demand Action ... I did it because there was really no nationwide grass-roots movement on this issue. In particular, I wanted to band together with other women and moms," Watts told The Hill.

"This was a crucial piece that was missing from the movement. You have some organizations that are think tanks, you have some who talk to gun owners," she added.

Giffords, formerly called Americans for Responsible Solutions, was also founded after Sandy Hook by Giffords and her husband Mark Kelly, who is running for Senate in Arizona. Their group is considered the most election-focused of the three, working to elect pro-gun control officials.

All the groups "coordinate very, very well and we agree on a lot," said Peter Ambler, executive director and founder of Giffords.

"You look at other sorts of issue spaces where there's profound disagreements around policy. You don't really see that here," he added.

"A lot of times people draw parallels between our movement and the marriage equality movement," Watts told The Hill. "There wasn't just one advocacy organization. There were many that worked together, taking different positions and talking to different groups of people, and that's really how that fight was won."

Those efforts are bearing fruit with the House vote this week on background checks.

"This really is the first place to start because the background check system is fundamental to gun violence prevention. It is the first line of defense to ensuring that guns don't get in the hands of individuals who are going to do harm to themselves or others," Hunter, from the Brady Campaign, said.

The Bipartisan Background Check Act is titled H.R. 8 in honor of Giffords, who was shot in 2011 at an event in Tucson, Ariz.

Hunter said there is "overwhelming public support" for tougher background checks.

Watts called the legislation "foundational."

"Once this is passed, you can look at other laws like the red flag law [and] closing the domestic violence loophole, also called the boyfriend law," she said.

The House is also taking up legislation to extend the deadline for federal background checks to be completed, giving officials more time to flag purchasers.

But despite the excitement over the vote, the groups still face an uphill climb in seeing the bills become law.

H.R. 8 is sponsored by Rep. Mike Thompson (D-Calif.) and currently has 227 Democratic co-sponsors, but only five Republican co-sponsors.

The NRA strongly opposes the bill and has mobilized its members against it.

"So-called universal background checks will never be universal because criminals do not comply with the law," Jennifer Baker, spokeswoman for the NRA, told The Hill.

"Instead of looking for effective solutions that will deal with the root cause of violent crime and save lives, anti-gun politicians would rather score political points and push ineffective gun control that doesn't stop criminals from committing crimes."

The bills are expected to pass the House but face long odds in the GOP-controlled Senate.

Gun control advocates say they know the challenges to getting gun violence prevention bills to the president's desk but see the vote as an important moment.

Still, a sweeping gun control package moving through Congress isn't conceivable, Robin Llyod, managing director of the Giffords group, acknowledged.

"We've had these horrific mass shootings and we've had a Congress that has taken virtually no action whatsoever. I think it would be very challenging if not outright impossible to move a gigantic package of policy," she said.

For now, the groups are also looking ahead to 2020 to build on their efforts.

The 2018 midterms saw a number of Democrats who made gun violence a prominent issue win election, including Rep. Lucy McBath (D-Ga.), whose son was killed in a shooting.

Moms Demand Action plans to again give out questionnaires to all candidates seeking an endorsement. Everytown gave out over 3,000 endorsements to both Republican and Democratic candidates for offices across the country that Moms Demand Action approved in 2018.

Giffords also hopes to be personally active in Senate races.

"We're excited to see already that so many of the candidates that are coming out and declaring for 2020 are bringing gun violence to the forefront. We look forward to continuing to work with them," Hunter said.