"I stand for..." is not necessarily, or even usually, the same as "I accomplish ..."
Join all the pro-gun groups you can.
But understand some things:
1) What the NRA was in 1934, what it was in 1968, and what it is now are very different things, both in terms of capacity and focus.
2) FOPA '86 was NOT, in ALMOST any way, a mistake. Many of the firearms freedoms we take for granted today were set up or re-established by that law. No-one, not the NRA, not the conservative politicians, not the bill's sponsors, not the president, thought the Hughes Amendment was going to be any kind of a major issue. The vast majority of gun owners (those groups represented) weren't exactly on fire over Title II weapons (didn't seem to care), and it was widely assumed that Hughes would be struck down immediately.
3) The focus of efforts on accomplishments that can be made today, and the bypassing of objectives that cannot be achieved today, does not indicate that those other objectives are not important and will not be fought for tomorrow -- or when the time is favorable.
4) If you want to support change and visible, positive movement on gun rights, give support to the NRA. If you want to give support to outlying fringe groups who stand for more "extreme" viewpoints (extreme, for the moment anyway), support JFPO, GOA, etc. They do some good things. They do NOTHING like what the NRA accomplishes. Not similarly, not kind of, not in the same league. They don't have the voice, and they don't have the access to the deal-making back end of Washington.
5) NRA is so much more than just NRA-ILA (not actually the same thing) that every gun owner benefits from NRA membership whether they support NRA-ILA or not.