The thing that's kind of tough about a "one size fits all" survival gun, is, not everyone is surviving in the same place or has the same survival needs.

Here in NJ/PA, I could probably get away with a pump .410 shotgun. Largest thing I've got to worry about here is black bear, and they're pretty rare. Otherwise, the most dangerous thing out here is other people and the largest of the wild game is probably white tail deer, with most shots being at a reasonably close distance.

But, in places like Africa, Alaska, the Great Plains, and others.....the situation is different. There is larger game, larger predatory animals, you might have to take further shots, ect. For those places, you might need something else, like a .300/.338 Win Mag or other high powered rifle round. A .410 wouldn't really cut it. The opposite is true as well, a .338 Win Mag bolt gun wouldn't really be what I would want to carry through NJ/PA.

Therefore, what you carry can be very dependent on location and what your individual survival entails. I don't think there is any single firearm that can do everything, for every place, effectively. So, I don't put too much stock in having one "do all" survival gun. I'd rather have the right gun for task, if possible.