I don't think 40 years of gunsmithing is "not knowing" his guns.
It sure is if he thinks ARs are no good. In my opinion.
It's a knowledge about availability issue.
I'm not sure what you mean, but the AR and parts for it, are THE most available gun/parts out there today, bar NONE. So if he KNOWS about availability, then the AR would be the first thing recommended, whether AR15 type or AR10 type. It's the penultimate in availability and modularity right now. Again, maybe not true in the past. Things are very different today from what they were just 15 or 20 years ago. Very, VERY different. As I say, good reason to self-educate, not listen to the old inaccurate conventional wisdom. I should say, his advice was perhaps accurate 20 years ago, but not NOW. The design has undergone literally hundreds of small innovations and improvements since the jammomatics of the 1960s military M16A1 rifles. You're really limiting yourself by relying on one person's opinion like that. In fact, why even come here and ask if he knows everything - just have him tell you what to do.
I said he is no longer an FFL these days
Right, which explains exactly why he's not "up to speed" on modern variants of proven designs. It makes perfect sense. Talk to someone who knows guns - someone who's been an FFL continuously for the last 5-10 years, through the present. I'm sorry, but the fact remains that you are getting BAD, INCORRECT advice. You can stick with it if you like, but it will be to your own detriment. I'm sorry - I'm sure he was quite knowledgeable at one time, but information is not a static commodity; it changed dramatically over time.
He says if you think AR's are good, then you don't know guns "in his opinion".
That's his opinion; that's great. But he'd be wrong, as 90% of the people on here would agree with me about, and disagree with him.
As far as need goes, no of course you don't have to explain it; but the reason I ask is because you said adamantly that you "NEED" one - not that you want one. It's quite possible that you have some particular function or competition in mind that would help us make a recommendation to you if we just knew what your needs are. Which is why I brought it up - if you're like most of us, it's just "cause I want it". But since you specifically chose the word need, I thought you have a more precise focus in mind. I'm just trying to help here. Maybe I didn't sound like it before, but I am.