"He's going to find out this is a country of the people, by the people and for the people. And he can't spend enough of his $27 billion to try to impose his will," LaPierre told host David Gregory on NBC's "Meet the Press," adding of the billionaire mayor, "He can't buy America. . . . Millions of people" from across the country are sending the NRA "$5, $10, $15, $20 checks, saying stand up to this guy," LaPierre said.
Bloomberg appeared separately on the program, which aired a day after his group, Mayors Against Illegal Guns, kicked off a $12 million, 10-state ad campaign calling for universal background checks.
"We demanded a plan and then we demanded a vote. We've got the plan, we're going to get the vote. And now it's incumbent on us to make our voices heard," Bloomberg said. " . . . This is about the public wanting to be safe on their streets."
The show aired 100 days after the Sandy Hook Elementary School shootings.
Gregory pressed both men on the issues of background checks, an unlikely to pass assault weapons ban and preventing the mentally ill from owning guns.
LaPierre sharply criticized Bloomberg's high-profile push for gun-control measures.
"He's so reckless in his comments . . . on the gun issue."
LaPierre said background checks would do nothing to keep criminals from getting guns.
"The whole thing of universal checks is a dishonest premise," he said. "Criminals aren't going to do this. It's a speed bump for the law abiding. It slows down the law abiding and does nothing for anybody else."
The Senate is expected to vote next month on gun control legislation.
A ban on assault weapons, which Adam Lanza used to kill 20 children and six educators before killing himself with a handgun, is not likely to be included. Bloomberg said that won't derail his efforts.
"I don't think we should give up on the assault weapons ban, but clearly it is a more difficult issue for a lot of people," Bloomberg said.
Gregory asked if some of the momentum surrounding gun control had eased as time passed from the shooting.
"It would be a great tragedy for this country and for tens of thousands of lives if it is lost," the mayor said.
LaPierre said checking mental health records during gun sales and providing armed security in schools are the most effective ways to prevent shooting massacres.
With Emily C. Dooley