The ads will run in the states of Republican Sens. Kelly AyotteKelly Ann AyotteAudit finds US Defense Department wasted hundreds of millions of taxpayer dollars US sends A-10 squadron to Afghanistan for first time in three years No, the US did not spend million on a gas station in Afghanistan MORE (N.H.), Saxby ChamblissClarence (Saxby) Saxby ChamblissLobbying World Former GOP senator: Let Dems engage on healthcare bill OPINION: Left-wing politics will be the demise of the Democratic Party MORE (Ga.), Dan CoatsDaniel (Dan) Ray CoatsPutin can learn from Gorbachev on how to gain from future US talks GOP senator blocking Trump's Intel nominee NSA nominee sails through second confirmation hearing MORE (Ind.), Ted CruzRafael (Ted) Edward CruzLesson from special election: Run on Social Security, Medicare and lower drug prices Conservatives balk over funding bill ahead of shutdown  Confirmation fight over Trump pick exposes blurred lines in GOP-LGBT activism MORE (Texas), Jeff FlakeJeffrey (Jeff) Lane FlakeBernie Sanders to Trump: Firing Mueller 'an impeachable offense' Overnight Health Care: House passes .3T omnibus | Bill boosts funds for NIH, opioid treatment | Senators spar over ObamaCare fix | 'Right to Try' bill heads to the Senate The Hill's 12:30 Report MORE (Ariz.), Chuck GrassleyCharles (Chuck) Ernest GrassleyGrassley on Trump calling Putin: 'I wouldn't have a conversation with a criminal' Lawmakers zero in on Zuckerberg GOP senator blocking Trump's Intel nominee MORE (Iowa), Dean HellerDean Arthur HellerRepublican drops Senate primary challenge to Heller after Trump's urging Three states where Dems can pick up Senate seats GOP senator: Justice Kennedy is going to retire this summer MORE (Nev.), Johnny IsaksonJohn (Johnny) Hardy IsaksonKey Republicans back VA secretary as talk of firing escalates Frustrated Republicans accuse Paul of forcing pointless shutdown Budget deal is brimming with special tax breaks MORE (Ga.) and Rob PortmanRobert (Rob) Jones PortmanLawmakers introduce bipartisan bill to speed up infrastructure permitting Overnight Tech: Zuckerberg breaks silence on Cambridge Analytica controversy | Senate passes sex trafficking bill | EU pushes new tax on tech | YouTube toughens rules on gun videos Senate passes controversial online sex trafficking bill MORE (Ohio), and in North Dakota, home of Democratic Sen. Heidi HeitkampMary (Heidi) Kathryn HeitkampDemocrats desperate for a win hail spending bill Koch-backed group launches six-figure ad buy against Heitkamp Overnight Defense: Senate sides with Trump on military role in Yemen | Dem vets push for new war authorization on Iraq anniversary | General says time isn't 'right' for space corps MORE.

The ads urge gun-control supporters to "remind Senator Heller: You work for Nevada, not the gun lobby."

OFA has not yet indicated which senators it believes are most likely to be swayed on gun control, but the first series of paid ads since the gun-control vote hints at the group's targets.

Ayotte is likely to remain a top target for gun-control groups, as a recent poll indicated she suffered among Democrats and independents in New Hampshire due to her vote, but she's not up for reelection until 2016.

Notably missing from the list are three of the other Democrats who voted no on the measure to expand background checks that failed in the Senate last week: Sens. Max BaucusMax Sieben BaucusFarmers hit Trump on trade in new ad Feinstein’s trouble underlines Democratic Party’s shift to left 2020 Dems pose a big dilemma for Schumer MORE (Mont.), Mark PryorMark Lunsford PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE (Ark.) and Mark BegichMark Peter BegichPerez creates advisory team for DNC transition The future of the Arctic 2016’s battle for the Senate: A shifting map MORE (Alaska).

Baucus will be retiring in 2014. Many observers consider his no-vote the result of constituent concerns, rather than political considerations, and don't see him as a likely vote in favor of gun control.

Baucus and Pryor, however, could face backlash from Democratic base voters if they're targeted on gun-control, a potentially crippling blow for the two senators, who face difficult reelection fights in red states next year.

But OFA Executive Director Jon Carson told The Hill earlier this week that the group isn't concerned about the potential political ramifications of attacks on red-state Democrats, and will target all senators who voted against gun control.

“No — we’re concerned about [them] not passing this background check bill,” Jon Carson, OFA’s executive director, told The Hill in an interview.