HELENA  — Most of the money funneling into the Republican primary for Montana’s open U.S. House seat is going to one candidate, leaving the others to look for ways to stand out and get their message heard in a crowded field.

In a new television ad, state Sen. Matthew Rosendale pretends to shoot down a drone with a rifle. He’s banking that image will play well in a libertarian-minded state such as Montana.

“This is how I’d look from a government drone, and this is what I think about it,” the Glendive Republican says in the ad, just before firing a shot in the air. “Spying on our citizens, that’s just wrong.”

There are seven weeks left before the June 3 primary and voters are really just turning their attention to the campaign to replace U.S. Rep. Steve Daines, who is leaving the seat to run for Senate. The winner will face the Democratic nominee, either former Sen. Max Baucus aide John Lewis or ex-state legislator John Driscoll, in November’s general election.

Four of the five Republican candidates are spending more money than they are taking in from donors, with the final push to the primary still to come. Despite that, their spending still falls short of former state Sen. Ryan Zinke, who in the first three months of the year spent five times what Daines did during his 2012 House campaign for that same period.

Zinke spent nearly $380,000 in the first quarter, and his ads seem to be everywhere on the Internet, television and radio. He has more than $423,000 left to spend thanks to an effective fundraising machine that has brought in donations across the nation.

That includes fundraisers at the Petroleum Club of Houston and help from Republican lawmakers from Texas, Alabama and Florida. In crisscrossing the country, Zinke raised more than $458,000 in the first three months of the year, but just as important, he’s building alliances with those lawmakers, he said.

“I spend a lot of time building coalitions. You can’t do this alone,” Zinke said in a recent interview. “You have to have a national footprint because that’s the only way you’re going to get it done.”

Zinke’s influx of cash has led Rosendale to try his more targeted message.

“You want people to pay attention,” Rosendale said. “It’s one component of the race.”

Rosendale acknowledged that he has no evidence of government drones spying on citizens. The ad is a metaphor for overreaching government regulations, he said, and he pointed to the phone and email data collected by the National Security Agency as examples of government snooping.

Rosendale has helped sustain his own campaign with a $500,000 loan. That’s allowed him to spend more than $244,000 in the last quarter and keep about $222,000 in the bank for the final push.

But his campaign only raised $33,000 from donors in that period.

It’s the same situation for the two other major candidates. State Sen. Elsie Arntzen raised about $70,000 while spending more than $81,000 over the period. She has a little more than $51,500 left to spend, thanks in part to a $63,000 candidate loan.

She was the last Republican candidate to enter the race, and she said she is only just building momentum by focusing her message on reducing the national debt.

Another candidate, former state Sen. Corey Stapleton, compared some campaign ads to Super Bowl commercials and questioned their effectiveness. In a Republican primary, it’s far more important to go to the towns, shake the hands of the voters and let them size you up, he said.

But he acknowledged that a lot of voters still don’t know who is running, and it will be important to make his case in the final weeks before the primary. He has more than $55,000 left to spend after raising about $43,000 in the last quarter.

The fifth candidate in the Republican primary, Drew Turiano, raised just $100 in the first three months of 2014, spent $4,400 and has $720 left, according to Federal Election Commission filings.