So now that everyone has given BWB some shit I think we should maybe address the question he asked.
I would like to applaud you for wanting to be on the group standard but it begs the question of why you feel the AR platform isn't reliable enough?
I would like to shoot steel and brass 223, and some ar's of almost every brand will not cycle it. I like the ar, its a very ergonomic rifle but when it comes to shtf gear im a no bullshit kind of person. So I want something that will go boom no matter how shitty Louisiana weather is.
What kind of ARs are you using? I've shot probably around 10,000 rounds of wolf ammo through ARs in the past few years, and I've had less issues than with M855 and PMC brass. This was with a midlength and a carbine length gas system carbines, don't know if it's different in rifle length or something else. A quality AR15 is also extremely reliable, provided it is lubed properly. Pat Rogers ran a BCM midlength like 40-50k with only like 3 cleanings and few parts replaced, he just kept adding more lube. Googleing "filthy 14" will pull up the article.
Part of the reason AKs like steel cased ammo better, is 7.62x39 and 5.45 have tapered cases, as opposed to straight wall cases like 5.56 and .308 have. I don't know of anyone who really runs a 5.56 AK hard, but I would imagine it would run steel cased 223 just as well, or poorly, as an AR.