A concurrent thread brings up the subject of a "Shit hits the fan" rifle; that one gun that many gun owners wish to possess but few will admit to having. The definition of such a rifle varies from person to person almost as much as the term SHTF does itself. So when does the fecal matter start flying? Is it when the Obama administration tries to place more restrictions on gun ownership? When a foreign army invades our soil? When a natural disaster strikes and leads to chaos not unlike that after Katrina? Truthfully, there is no set expectations for what will cause a SHTF scenario; all that needs to happen is a disruption of life as we know it.
Now, on to the rifle itself. While the definition varies from person to person, there are a few characteristics that are desirable:
1) Reliable and easy to maintain (parts replacement or fabrication is another consideration)
2) Accurate (a touchy subject, but even a 3-MOA rifle is more accurate than most shooters under stress)
3) Plentiful ammunition, not just on-hand but capable of being resupplied
Most will agree with those basics, and I am sure many have more specific requirements, but you get the gist of what a SHTF rifle is.
Over the years my own definition has changed quite a bit. I'll share more on it later.