By KENNETH P. VOGEL and MIKE ALLEN | 10/14/14 5:04 AM EDT Updated: 10/15/14 4:46 PM EDT

The deep-pocketed political network created by the billionaire conservatives Charles and David Koch this summer quietly launched a super PAC that can buy explicitly political ads supporting Republican candidates rather than the issue-oriented ads they‘d been airing for years.

The catch: For the first time, the network’s donors would be publicly identified if they gave to the super PAC.

Four months later and the results are in: The super PAC, Freedom Partners Action Fund, is a smash hit with donors. It has surpassed its fundraising goal and now says it is on pace to spend roughly $25 million on ads intended to help Republicans capture the Senate.

POLITICO was allowed to review an advanced copy of the mandatory report the super PAC will file Wednesday with the Federal Election Commission that will formally reveal the names of some of the Kochs’ ultra-rich conservative donors. The report, combined with additional information voluntarily provided by Freedom Partners Action Fund, are illuminating, testing some of the conventional wisdom surrounding the Koch political operation.

New York hedge fund billionaire Bob Mercer wrote the largest check — $2.5 million — followed by Charles and David Koch, who each stroked $2 million checks from trusts in their names. The group received $1 million apiece from Arkansas poultry producer Ronnie Cameron, Wisconsin roofing billionaire Diane Hendricks and Nebraska trucking magnate Clarence Werner.

“I just felt like it’s time to stand up and put my money where my mouth is,” said Cameron, who made his donation in two equal checks through Mountaire Corp., the Arkansas-based poultry company he owns. Cameron donated at least $1 million in 2011 to non-disclosing groups in the Koch network, but the contribution to Freedom Partners Action Fund was far more than he’d ever given to any political committee that lists its donors. He admitted he thought long and hard “about getting the publicity because most of us are private — I work very hard to keep my name out of stuff.”

“I just kind of decided that it was more important to support it than it was to maintain my privacy,” Cameron said. “I’m 69 years old. I’m much more concerned that my grandkids could be living under communism, or something like it, with the type of leadership that we have right now.”

While the Kochs’ political operation is often portrayed as being entirely supported by the billionaire brothers, roughly 650 donors combined to contribute the more than $15 million raised by the super PAC’s from its June creation through the end of September. The majority of the donations were smaller than the $200 threshold that triggers FEC disclosure requirements, and as such, aren’t listed in the report, which doesn’t include continued brisk fundraising this month, during which Freedom Partners spokesman James Davis said the PAC was expecting to bring in an additional $10 million.

The ability to quickly corral such a robust war chest for a type of political spending that was once dominated by the Republican Party and its big-name operatives like Karl Rove further demonstrates the Koch network’s evolution from a guerrilla band on the libertarian fringes of the right to arguably the preeminent force in conservative politics.

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