when i think of, SHTF, a reliable tough bolt gun or AK mod comes to mind. Don't get me wrong, i love the AR design, and i'm sure that they're great, reliable rifles, but think of it in terms of "which gun TYPICALLY needs the least maintainence/ parts?"
I'm not trying to insinuate that ARs are fragile and require lots of care, because i know most of them arent, but i dont see them adding up to a well-built bolt action rifle in terms of longevity.
just my humble opinion