By Daniel Trotta

Aug 5 (Reuters) - About 100 protesters, many wearing T-shirts emblazoned with "NRA = Not Real Activists," marched through the National Rifle Association's annual meeting in Dallas in May to slam the powerful gun lobby as too conciliatory on gun rights and rally for their candidate for the board.

Adam Kraut, a gun rights lawyer, fell about 4,000 votes short of the 71,000 needed for election, but earned 5,000 more than the previous year, a sign of the growth of the Second Amendment purists within the NRA known to many as "gundamentalists."

With opinion polls showing U.S. public support for more gun control growing in the wake of mass shootings in recent years, the NRA is facing internal pressure from this little-known force that is demanding that the leadership concede zero ground to gun-control advocates.

Its rise has rattled the NRA leadership and threatens the association's ability to hold on to moderate supporters and to make compromises that might help fend off tougher gun control measures, according to some of the two dozen gun-rights activists, policy experts and gun-control advocates interviewed for this story.

"Generally, they have a disproportionately huge amount of power in the gun-rights movement," said Richard Feldman, a former NRA lobbyist.

The NRA has faced divisions before. An internal revolt at the 1977 meeting in Cincinnati turned the polite, sport-shooting organization into a bare-knuckled political lobby that today claims five million members and is closely aligned with the Republican Party, funding pro-gun politicians. The NRA, which spent $30 million to support Donald Trump's 2016 presidential campaign, is often viewed by gun-control advocates as implacably opposed to tighter gun laws.

The NRA leadership has put up obstacles to Kraut's election, both with bylaws that make it harder

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