Yes, the NRA certainly is a single issue organization. Their support of libtards like Harry Reid, or in the past, Bill Richardson, was pretty much a deal breaker for me, but they probably are the largest and oldest 2A org out there. I do support GOA. The National Association for Gun Rights has such close ties with both the Paul’s that they seem to be just another Paul PAC. This article is dated, but gets the point across: http://www.opensecrets.org/news/2013/04/gun-rights-group-with-close-ties-to/
I like GAO also and I like JPFO. I am not Jewish but I joined because I like their style.