For some people, it's not so much TEOTWAWKI, as it is being prepared and knowing how to live "off the grid", and off the land. My wife and I have done some research on what would be different and what would be needed, if the veneer of civilization were to peel off, leaving folks to fend for themselves. Our goal is simply to not be as tied into, or as dependent on, all of the "modern" aspects of life. Part of that is having the resources to defend ourselves and grow/harvest/store our own food. There is something very rewarding and comforting about knowing a few of the old-school skills that people used before you had a fridge in every house, a supermarket in every town and the Internet at your fingertips. Reloading is one of those skills, as is casting your own bullets.
If you ever get a chance to spend a week or more completely isolated from the vast majority of electronic contrivances, I highly recommend you give it a try. It might give you a different perspective on why you have guns and how they might be used, in a worst-case scenario.