A conservative super PAC that has begun airing an ad attacking Rep. Jack Kingston (R) in the crowded Republican primary for U.S. Senate in Georgia says its strategy is to help one of his opponents, businessman David Perdue (R), according to a disclosure form that lays out its plans.

In a letter authorizing a media company to handle its ad placements in the race, Citizens for a Working America PAC says such communications with the public "will independently advocate for the election of David Perdue and/or for the defeat of his opponents." The letter, dated April 16, is posted on the Federal Communications Commission's Web site.

The super PAC recently went up with a $500,000 TV ad buy against Kingston that dubs him a "career politician" and hits him for supporting earmarks and voting to raise the debt ceiling. A telephone message left with the group seeking further information about its strategy was not immediately returned.

Citizens for a Working America PAC was formed in 2010, when it devoted six figures to defeating then-Rep. John Spratt (D-S.C.). In 2012, it supported Rep. Michele Bachmann (R-Minn.) in the presidential primary then later backed Mitt Romney.

The group likely received a recent infusion of cash. According to its campaign finance report, it had just $91 on hand at the end of March.

The organization  is the second super PAC to hit the airwaves in recent weeks. Ending Spending Action Fund has released ads targeting Rep. Phil Gingrey (R) and Democrat Michelle Nunn. The group isn't publicly backing a candidate. The GOP field also includes Rep. Paul Broun and former secretary of state Karen Handel.

The U.S. Chamber of Commerce recently endorsed Kingston -- a sign it may be preparing to hit the airwaves it support him.

The primary is May 20. Most observers expect the Republican race to head to a runoff, which would be triggered if no candidate get a majority of the vote.