I want something that is:
- reliable
- reasonably accurate
- chambered in a commonly available (loaded or components), reasonably powerful cartridge with 100+ yd effective range, 300+ would be better (we're talking SHTF here, I don't want to literally be caught short)
- mags and common breakage/wear parts available for purchase now
- handy size and weight so it can be carried all the time and possibly concealed (I have a slight build, 5' 11" and 150 lb, so rules out battle rifles and such)
I settled on SBR'ed AR-15s in 5.56mm, and my (kept in a free state) "SHTF" rifle is a suppressed 12" SBR with a BCM upper, holosun red dot, two-point sling and weapon light. I have some 10.5" PDW setups with compact stocks and linear comps that are super handy to carry.
My MAssified SHTF rifle is a ruger PC carbine with red dot, two-point sling and weapon light.
The takedown PC carbine is super handy for that, as are the 10.5" rifles which can be carried assembled in a backpack or tennis racket case.
I think the biggest thing isn't the rifle you have, it's TRAINING. Know how to shoot and move, use cover and concealment, how to communicate, bounding cover with a buddy, move in buildings and built-up areas etc., and of course how to reliably hit targets from unsupported firing positions under stress. Also, knowing how to use a tourniquet is nice.