I just talked to such a person tonight who is deeply knowledgable and has always been generous of his time with me. That's what I like about him the most; he is very willing to share his knowledge and even say when he doesn't know something but hey, call this guy because he knows more than I do. That's humility, which can be a little scarce around gun guys sometimes as we know. I consider him to be a friend who I can trust, who won't steer me wrong around info or potential purchases.
He also has a lot of truly good vintage guns. At one point, he owned THE Selous rifle...lots of howdah pistols, best quality guns, etc. I will never forget the first time he walked me through some of his collection and seeing best quality and rare items coming out of the woodwork (literally). I think my jaw was just hanging open. Makes me smile thinking about it.