Survival rifle?
I think I'd have to say an AR-15. I don't know of another round that can adequately kill squirrels and other small game but also take deer.
I can. In fact, everything from .22LR on up can do it. What differs is the range you are able to use, and how much work you have to do.
Lets get a few things straight, just what kind of "survivial" are you thinking about? We don't do the "zombie apok-key-clips" here, nor TEOTWAWKI threads, so count those out right now.
SO, what is left? Two basic situations. One, survival in the wilderness. Two, survival in civilization without basic law & order and food distribution services in
your local area. (like a hurricane aftermath).
Now, both of these things have one big thing in common, they are TEMPORARY.
People who choose one gun & caliber, based on what ammo is commonly available on the shelf , (such as choosing a .223 over a .22 Hornet, for instance) are missing a vital point. And that is that in a survival situation, NO AMMO IS AVAILABLE. All there is that you can count on is what you already have. PERIOD.
SO, everything is "available" right now, and nothing will be available in a disaster/lost in the wilderness situation. Think you are going to go to the local store and get some ammo in a survival situation? Think again.
People who choose a caliber based on the weight of the ammo MAY have a point, but realistically speaking, how much ammo are you going to need? HOW LONG do you think you are going to be in a survival situation? A week? possible, a month? highly unlikely.
But lets say a month, and lets say you're a lousy hunter and you need 3 shots average to bag a rabbit, or whatever. 100rnds will cover that for a month. Should cover that more than adequately, considering you aren't likely to be shooting every day. One deer will feed you for several days, even under totally primitive conditions, of course there will be a large wastage, and you might not like what you have to eat, but survival isn't a sport or a game. And, really, a month isn't realistic, unless you cannot move, and if you cannot move, hunting becomes a real problem.
Some have suggested silencers. While not needing earplugs is a nice benefit, why on earth would you need to be silent? Most folks, lost in the wilderness would be pretty glad to be found by someone (again, forget the evil hordes of whatever). Why would you need to hide?
One place where I can see a use for a large capacity repeater would be defense against a pack of wolves, or feral dogs. And a handgun will fill that role pretty well.
Several have spoken against the shotgun, mostly because of the weight of the ammo. Again, same things apply, how much you gonna need, do you think? Two boxes of 12 ga are a fair bit, but again, if you aren't stupid, (and assuming there is game to be taken), you are going to be returning to civilization (or it to you) at some level before you have shot up all of it.
Wilderness survival means more than just food. And for getting food, snares and general woodcraft go further than ever a good rifle. Also, where are you having to survive? A rifle & ammo are more useful in the woods than the desert.
And if its sitting home, waiting for the power to come back on, and worried about looters, etc. That is a different situation.