The ads will run in the states of Republican Sens. Kelly AyotteKelly AyotteOPINION: Democracy will send ISIS to the same grave as communism Kelly Ayotte joins defense contractor's board of directors Week ahead: Comey firing dominates Washington MORE (N.H.), Saxby ChamblissSaxby ChamblissFormer GOP senator: Let Dems engage on healthcare bill OPINION: Left-wing politics will be the demise of the Democratic Party GOP hopefuls crowd Georgia special race MORE (Ga.), Dan CoatsDan CoatsThe Memo: GOP pushes Trump to curb Mueller attacks Merkley: Trump 'absolutely' tried to intimidate Comey Coats: Trump seemed obsessed with Russia probe MORE (Ind.), Ted CruzTed CruzHealthcare wish lists: What moderates, conservatives want Overnight Healthcare: GOP infighting erupts over bill | How Republican governors could bring down ObamaCare repeal | Schumer asks Trump to meet with Dems GOP infighting erupts over healthcare bill MORE (Texas), Jeff FlakeJeff FlakeOPINION: ObamaCare by another name is still ObamaCare Senate should seek to retain its 'blue slip' tradition for judicial nominees Progressives target Heller and Flake on Senate GOP bill MORE (Ariz.), Chuck GrassleyChuck GrassleyGOP senators want surveillance requests from FBI Russia probe Overnight Cybersecurity: New ransomware attack spreads globally | US pharma giant hit | House intel panel interviews Podesta | US, Kenya deepen cyber partnership GOP chairman wants 'robust' tax reform process in the Senate MORE (Iowa), Dean HellerDean HellerOvernight Healthcare: GOP infighting erupts over bill | How Republican governors could bring down ObamaCare repeal | Schumer asks Trump to meet with Dems GOP infighting erupts over healthcare bill Budowsky: Rising up vs. TrumpCare MORE (Nev.), Johnny IsaksonJohnny IsaksonFood Network star honors veterans with dessert feast The Hill's Whip List: GOP undecided, 'no' votes pile up on ObamaCare repeal bill Georgia special election runoff: live coverage MORE (Ga.) and Rob PortmanRob PortmanHealthcare wish lists: What moderates, conservatives want GOP infighting erupts over healthcare bill Our national parks need updates; Congress can help MORE (Ohio), and in North Dakota, home of Democratic Sen. Heidi HeitkampHeidi HeitkampSenate Democrats: ObamaCare repeal fight isn't over yet Dem senator: Don't bet against McConnell on ObamaCare repeal Senate Dem undecided on 2018 reelection run 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 BaucusLawmakers: Leave advertising tax break alone GOP: FBI firing won't slow agenda White House tax-reform push is ‘game changer,’ says ex-chairman MORE (Mont.), Mark PryorMark 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 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.