My end-of-civilization rifle is a .223, for exactly that reason.
We aren't the people who have spent the last thirty years standing on street corners shouting at nobody. We're calm, rational, reasonable people, and we're starting to consider civilization collapse in the same way we've discussed market downturns and foreign affairs in the past. In my mind, it's past "crazy" and "theoretically it could happen" to "it's possible." In some cities, I think it's past "it's possible" to "how soon?"