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 Baucus (Mont.), Mark Pryor (Ark.) and Mark Begich (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.