'You can't shoot for the moon every time': Paul Ryan

Rep. Ryan: You can't shoot for the moon every time

The elusive "grand fiscal bargain" will not be reached while "this president" is in office, House Budget Committee Chairman Paul Ryan told CNBC on Thursday.

That's why this week's small bipartisan budget deal is the best approach to chip away at the nation's spending and debt problems, he insisted in a "Squawk Box" interview.

"You can't shoot for the moon every time," Ryan declared—when describing the framework he helped craft with his Senate Budget Committee counterpart, Sen. Patty Murray, D-Wash.

"Senator Murray and I decided to focus on common ground," the Wisconsin Republican said. "If I can't get a mile, I'll take a step."

(Read more: Budget deal a 'joke and betrayal': Stockman)

"We knew ... that if we required that the other person [to] violate their core principles, we'll get nowhere," he continued. "That's why all these grand bargain talks go nowhere."

Rep. Ryan: Getting a budget is our ultimate goal

Despite tea party rancor, the bipartisan agreement is expected to be approved by the GOP-controlled House as soon as Thursday. "We have the majority of our majority" on board," said Ryan, who was Mitt Romney's vice presidential running mate in the 2012 election. "We're in good shape in the House."

(Read more: US budget deal headed to vote, passage predicted)

The deal unveiled Tuesday includes $63 billion in sequester spending cut relief, in exchange for $85 billion in savings elsewhere. In an op-ed for the National Review Wednesday, Ryan described the bottom line of the budget agreement:

"This bill will reduce the deficit by an additional $23 billion, without raising taxes. And most important, it will cut spending in a smarter way."

"This is a constitutional step in the right direction, reclaiming the power of the purse. It prevents shutdowns, which we think are bad distractions ... and inject uncertainty in the economy," Ryan said—though he insisted it's not a substitute for the Republican desire to make deep spending cuts and overhaul entitlements.

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But to get true budget reform, he admitted, Republicans are going to have to win some more elections. "I don't think we're going to have this grand fiscal bargain with this Congress, with this Senate, with this president."

Ryan concluded that his budget deal is a good template for further steps in this environment of divided government.

By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.