"The only thing this audio proves is that Matt sought the endorsement of the NRA -- and we're proud to have it," Scanlon said. "Matt and the NRA have never discussed anything beyond the organization's membership and endorsement process. "

NRA-ILA spokeswoman Jennifer Baker also denied campaign coordination by her group. "At no time did NRA-ILA discuss any communications or activities beyond our membership with Matt Rosendale or his campaign. Any assertion otherwise is completely false."

Brendan Fischer, an attorney with the Washington, D.C.-based Campaign Legal Center, said it appeared to him that Rosendale was speaking about NRA spending money on ads in the race, because that was the question he was answering.

"It appeared from the recording that Rosendale was talking about something other than an endorsement," Fischer said. "It creates an inference that the NRA-ILA had suggested what kind of communication it would be running in the Montana Senate race, and Rosendale assented, which would be coordination."