Some gun owners, saying that the National Rifle Association isn't battling hard enough for their rights, are taking the fight into their own hands.
The 4.3 million-member NRA, one of the most powerful and well-funded lobbying groups in Washington, has for 35 years dominated the push to expand gun rights.
But its strategies aren't aggressive or imaginative enough for some gun owners who want to openly carry holstered pistols in public places, or to exploit loopholes in state gun laws to purchase semi-automatic rifles.
They are coming together in smaller, loosely organized groups that recruit on the Internet and find inspiration from the tea party movement.
On Monday, several thousand gun owners plan to mount two protests—a march in Washington and an "open-carry" rally in Mount Vernon, Va.
"More and more the gun-rights movement is moving toward a stand-up-and-shout approach," said Jeff Knox, director of the Firearms Coalition, a for-profit, loose-knit coalition of activists. "There's a lot of general frustration with NRA not taking a hard enough line."
Data on how many owners are joining the splinter groups are scant, because many are newly organized, and tend to seek contributions over formal memberships. In addition, some gun owners join more than one group. Mr. Knox estimated that the splinter groups had one million to 1.5 million members or regular contributors.
The NRA is "no longer absolutely the 800-pound gorilla" in the pro-gun movement, said Gary Marbut, a life member of the NRA and president of the Montana Shooting Sports Association, an NRA affiliate. "The NRA is running the risk of becoming insignificant, of fading into the background."