So the NRA has just over four million members, and the lower tier of membership is $35 to join.
The NRA is both a 501c3 and a 501c4, meaning it has to comply with laws concerning governance for non-profit charities as well as organizations involved in political activity. There is a 76-person board (typically large boards are done in non-profits to effectively reduce control to the paid leadership of the organization) but like all such organizations these board members must be elected. The board members are elected to three-year terms by ballot by mail.
So it's a dangerous tactic, in that it would give the organization another $100 million plus, but if we got 4 million people who wanted to disband the NRA to join the NRA, we could be done with these people for a while. (This tactic was tried on the Sierra Club some time ago, note.)
Yes, they would pop up like whack a mole in another organization, but think of the delightful organizational chaos. Several million members would immediately give those who wanted to change the political activities of the organization standing, and allow legal maneuvering to force the NRA to obey the sunshine laws required for non-profit management, or have it decertified as a non-profit organization. And if the brand can be hijacked, so much the better.
"Conservatives" did the same thing with the Republican party, in essence, with the tea party.
Now, to do this correctly, we'd have to do it all at once. If we trickled in the membership, it would appear as if the NRA support was gaining and the financial resources would go to the organization now. (Note that the current budget is already $250 million, so they're getting more than half their money from big donors, most notably the gun manufacturers.) So if we set it up with a petition, and the commitment of those signing the petition was to join as soon as there were 4.3 million signatories, it would be a triggered event.
I note that it probably is not necessary to get an actual majority, since typically large organizations have low turnouts for board elections. The NRA is a bit of an exception, since there are many suborganizations (you know, Nutjob AR-15 Owners Association, Collectors of Killing Machines of America, et alia) that actively lobby for board seats, but the turnout is still in the 10 percentage range. So hypothetically we'd only need a half million new members or so.
I'm not sure whether this is a proposal that would work, and we'd have to have good legal minds lined up in non-profit law and an organization along the lines of Teamsters for a Democratic Union ("People with Hearts and Brains for a Democratic NRA"), but it's time to give even current NRA members who are not batshit crazy a voice and put some pressure on their leadership.
To coin a phrase, the best defense is a good offense.
Ideas? Alternatives that would attack this cancer at its base instead of with the ineffective peripheral anti-gun organizations that exist? (I gave up on several of these a long time ago for being toothless and craven.)