New York Mayor Michael Bloomberg's super PAC is getting involved in the special election to replace former congressman Jesse Jackson Jr. (D-Ill.), launching a new ad against NRA-backed former congresswoman Debbie Halvorson (D).

“In the race to replace Jessie Jackson, watch out for Debbie Halvorson. When she was in Congress before, Halvorson got an A from the NRA," says the Independence USA ad. It concludes with: "Debbie Halvorson: when it comes to preventing gun violence, she gets an F."

Halvorson represented a more moderate swing district for one term before losing in 2010. Now she's running in a redrawn district that includes some territory she represented before but also stretches into urban Chicago.

There is no word on exactly how much is being spent on the ads (it is only called a "significant" buy in the press release), but the super PAC spent millions on some House races late in the 2012 election and hasn't been afraid to spend heavily to make an example of an NRA-friendly Democrat.

Halvorson has said she does not support President Obama's proposal for an assault weapons ban or banning high-capacity magazines.

She is one of more than a dozen Democrats seeking the party's nomination in the heavily Democratic district.