A Magellan Strategies survey released Tuesday finds the six-term senator clinging to a 2-point edge over challenger Richard Mourdock, 44 percent to 42 percent, ahead of next week’s GOP primary.

Fourteen percent of likely primary voters remain undecided.

Magellan conducted the poll on behalf of the Lunch Pail Republicans, a labor-friendly group that has endorsed Lugar.

““This looks like a turnout battle,” Magellan pollster David Flaherty said in a brief interview.

While the data reaffirms how tight the contest has become, it also parts with a Wenzel Strategies survey released last week showing Lugar trailing by five. That poll was paid for by Citizens United, which backs Mourdock.

The Magellan survey of 400 Republicans, conducted Tuesday by phone, reveals a gaping gender gap between the two candidates. While Lugar leads Mourdock by 11 points among women, Mourdock enjoys an 8-point advantage among men.

Mourdock held a 42-point advantage among self-described “tea party” members, 62 percent to 20 percent. Among those who do not consider themselves tea party members, Lugar leads 64 percent to 19 percent.

Self-identifying “conservatives” side with Mourdock, but only narrowly, 42 percent to 38 percent.

“It’s a dead heat,” Flaherty said. But he added, “Turnout’s been low there. I would expect low turnout more likely to help Mourdock.”

The Mourdock campaign dismissed the poll, again pressing the Lugar campaign to release its own internal numbers.

“If Senator Lugar was leading, then why hasn’t his campaign put out poll numbers in months, and why did his largest SuperPAC just write the race off this week, refusing to spend another dollar helping him?” asked Mourdock spokesman Chris Conner. “Recent independent polling has showed conservative Richard Mourdock in the lead, and we expect to finish first on election night.”

On Friday, the American Action Network, a Super PAC supporting Lugar, acknowledged it had pulled its resources out of the Hoosier State in order to “let this race play out.”

Indiana Lunch Pail Republican chairman David Fagan said his group commissioned the poll to assess whether or not to deploy resources to help Lugar.

“After looking at the numbers, we felt it was the appropriate time to get involved,” he said. “We will help in several ways trying to get people to volunteer. We will be phone banking. I was pleasantly surprised that at this time our poll showed Sen. Lugar was in the lead, but clearly it’s a close race.”

Mourdock also scored another high-profile endorsement Wednesday, landing the backing of former presidential candidate Michele Bachmann.

“I am happy to endorse Richard Mourdock for the U.S. Senate today. Richard is a true conservative and we can count on him to stand up for Constitutional conservatives values,” the Minnesota congresswoman said in an afternoon statement.