It isn't so much that end of the world threads are fundamentally counterproductive, it's that we get questions like this and the answers are necessarily unhelpful.
Define your 'rainy day.' If you're not a hunter, learning on the fly is going to be tough. Do you want a man stopper, a deer hunting rifle, a squirrel gun, something that can harvest wild hogs?
How much ammo can you afford to stockpile?
What kind of land do you live on? Is it wide and open, mountainous, dense forest?
Do you plan on moving around much, or staying in one place?
All you have to do to get around the 'end of the world' ban is to start a thread and say, 'Recommend me a lightweight, reliable autoloading rifle suitable for harvesting 40lb game and discouraging two-legged predators. It should take common ammunition and be short and handy in thick woods.' Edit, of course, to your own needs. You get the answer you want and the discussion will be helpful to others as well!