Mailing lists get circulated like blood through your veins. Just part of bidness.
I once asked for some information under the name of Pyotr I. Tchaikowski.
It was fun watching the mispellings and variations on stuff I got through the mail for the next year from every company in the world... well, maybe every other company in the world.
While membership in a pro-RKBA (Right to Keep and Bear Arms) organization of your choice is always desirable, the NRA is the 500 lb gorilla with respect to fighting for RKBA in Congress... and elsewhere.
Whichever RKBA organization you choose, you will always find something to bellyache about... that's the nature of any organization, so don't let that bother you too much.
I can even complain about thehighroad dot org (THR) if I put a mind to it, but that doesn't mean that THR is not a wealth of information and a lot of fun.
It takes bucks, and big ones, to counter the very well-financed anti Second Amendment forces in the country, and indeed around the world, so you can expect solicitations for money fairly often.
For now, though, just join, and add yourself to the millions of gun owners across the country.
You and three million* others are what make it the 500 lb gorilla.
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* Membership number subject to correction by anyone. I haven't kept track lately.