I think if you were to target the more active gun shops, and gain their buy-in to actively collaborate (be it via entry discounts, a free ad in the newsletter, etc) and get them to agree to proactively promote GOAL/Comm2A/GONH membership with their patrons, you might see the needle move a bit. Could you imagine what would happen if Carl at FS advertised, "%5 off any single purchase with a new GOAL membership?" Now get 4-6 of the high volume shops in the state to do that. Maybe it's not 5%, maybe it is a promo gift or something along those lines, of a gift cert for the next purchase when they come back. Or a rebate when they return with their GOAL membership card. We're a bunch of cheap bastids, money gets our attention quickly.
Once you get the mailing list, it is up to GOAL to win hearts and minds moving forward.