Survival . . . ?
Pick a Scenario of your choosing. Would you rather have an Ar variant, an AK, or an SKS? Why?
I live in a place where a "survival rifle" isn't a frivolous consideration.
The rifle I carry in the truck is a Marlin P70SS, (Papoose, .22LR take-down rifle). Along with it is some 600 or so rounds of various .22LR ammo, including CCI Stingers and such.
If I'm "caught with my pants down" out in the woods, or even several minutes from home, that's what I'll have on any given day of the week, whether there's a pistol in the mix or not.
Now, if I had some kind of heads-up that there might be a heavier emergency on its way to a neighborhood near me (exceptionally bad weather, social unrest, whatever) and if I had time to make the adjustment in advance, and if I were constrained to the original list of possibilities, I'd take the nearest thing I have to
"an AR variant" -- my SU-16A -- and keep that handy.
It's AR-mag compatible, weighs less than 5 lbs, folds up for pack carry, has a low-maintenance piston/op-rod system, eats common ammo, is rabbit-accurate inside a hundred yards, is effective and heads-down accurate at 300.
I should probably get a scope for it. Never can tell when you'll need rabbit accuracy at 200 yards.
So much for playing by the rules.
If I get to pick from my stable, I might well pick something a little more versatile. I'm kinda with Brian on the 1894C. It's good for pretty much anything from rabbit to elk.
It's mechanically simple so, if you're at large for an extended period, maintenance is generally not a burden. It uses a common ammo family with a wide range of loadings. It's a common-looking machine that doesn't broadly inspire dread, yet the effectiveness of the "plain old cowboy rifle" is well enough known that you won't have folks "volunteering to be first" when things get tense.
If we change the scenario to "only what you can carry" then ammo quantity becomes a large factor, and -- assuming it's a "stay alive and stay fed" kind of situation -- the venerable .22 rises to the top of the list. Only, given the choice, I do believe I might go with the Marlin 39A. Yes, it's twice as heavy as the Papoose, but it has an 18-round magazine (the Papoose has six or seven) and I've just found out mine is minute-of-baseball-accurate at 75-100 yards -- better if I'm shooting from a rest.
Those are my most obvious picks. If we do some contortions and cook up some more obscure scenarios, I might grab something else.
Heck, if I knew that rate-of-fire would be more important than flexibility, and I needed something light, compact, and ordinary-looking, I'd likely grab the M1 Carbine. Ammo is lighter and more compact than most other rifles, and in rate-of-fire contexts you're less worried about rabbits and more worried about keeping the social unrest
du jour at a distance.
"Survival" has so many possible contexts that you might well write a small book and not exhaust the possibilities.