Kelly Ayotte (R-N.H.). Sen. Kelly Ayotte (R-N.H.)

The fight over gun restrictions has moved from Capitol Hill to New Hampshire, and when it comes to spending, the pro-gun control groups are winning.

Ads in the state are focused on Sen. Kelly Ayotte (R), the only senator from the Northeast to vote against expanded background checks. Gun-control groups hope to turn her vote into a political liability; gun-rights advocates aim to prove that it isn't one. 

American Future Fund, a conservative nonprofit, is up Friday with a $250,000 ad buy supporting Ayotte. That dwarfs the $25,000 buy from the National Rifle Association. But it pales in comparison to the ad buy from Mayors Against Illegal Guns, which is estimated to be larger than $600,000. (The group says only that the two-week buy is in the six figures but has not disputed that estimate.) The ads are running during Red Sox games, an expensive time. Americans for Responsible Solutions, the pro-gun control group founded by former congresswoman Gabrielle Giffords and her husband, also has a $350,000 radio buy up in New Hampshire and four other states. The group has raised $11 million in the past four months and is likely to spend more in New Hampshire.

The NRA spent about $18 million on the 2012 election, so the fight here is hardly over. AFF is also vowing to go toe-to-toe with gun control groups. But for now, New Hampshire residents are hearing a lot more criticism of Ayotte's vote than praise.