I'm one of the OP's AR owning friends and the place he's probably getting at least some of his anecdotal evidence.
I had a couple of ARs before he got his Mini. Since he's gotten his Mini, we've done a little teasing back and forth about which rifle is "better" or "cooler". From my end anyway, it was never intended to be anything more than good natured teasing between friends. Maybe he's catching legitimate flak from other places though...
Now, then - I own 2 ARs. I bought the first one a few days after the AWB ended. It's a DPMS M4 with a chrome lined barrel. When I first bought it, all I had was Wolf ammo for it, and it ran fine. Later, after running 1,000 - 1,500 rounds of Wolf through it, I started to have problems with Wolf cases getting stuck in the chamber when the rifle got hot. Usually, I was able to knock the stuck cases out with a cleaning rod, but occasionally I'd have to wait for it to cool down before being able to knock the stuck casing out. Around this time, I noticed that I never had those problems with brass cased ammo. For that reason, I started to spend a little more to get better (IMO) brass cased ammo and stopped buying Wolf.
Now, maybe I had those issues because I didn't spend enough time using the chamber brush when cleaning it. I still really don't know why Wolf stopped working reliably seemingly all of a sudden. I've also heard that DPMS ARs are known for having fairly tight chambers so that might contribute too.
In any event, when I got my 2nd AR (a 16" CMMG mid-length), I decided not to even try running Wolf in it since I've had trouble with it before (albeit in my other AR), and I have plenty of brass cased ammo now. As someone else mentioned earlier in this thread, CMMG's policy is that using Wolf or other steel cased ammo will void the warranty so that's another reason to avoid steel cased ammo if at all possible.
Still, it's possible that the steel cased ammo like Wolf would work fine in my CMMG and maybe in the DPMS again now that I've started using the chamber brush more during cleaning. In any event, it's likely that the OP is stating that ARs are picky about ammo because 1 person he knows had trouble with Wolf ammo in 1 AR. Obviously, that's not a large enough sample size to identify any trends.
I don't hate Mini-14s either. I just own ARs instead because that's what I'd rather have. I think everyone should buy what they like best and/or what works best for them. That's why I tell everyone that asks me what they should buy to try before buying if possible and buy what they like.
I know this was long winded, but hopefully this will clear up a few things a little.
