I've been rolling this point around in my head for awhile, but wanted to get some good opinions on the topic. What I mean by ammunition diversity is the choice between limiting the caliber of your firearms collection or maintaining a wide diversity, for SHTF situations or just keeping the cost down. For example, I'm considering a carbine such as the Hi-point, Kel-Tec's, etc, and was thinking about the caliber I would like it to be. If I stick to 9mm as much as possible, can I reasonably expect that 9mm ammo will continue to be reasonably available? I don't reload (yet.) Or do I try to vary the calibers to ensure that something I have will fire what's available? What calibers would folks reasonably expect would continue to be readily available for the long term (internal and external politics taken into account to some degree?) Knowing that there are some really neat firearms out there that require slightly harder to find loads, I think its reasonable to avoid those (at least initially) because lack of availability will render those firearms useless. I'm not interested in stockpiling a ton of ammo at this point, since I'm short of good places to store it in my home and my wife and kids haven't gotten completely used to me stockpiling ammo just yet. Currently, no two guns in my home shoot the same ammo, although they're still fairly common calibers, hence my question for the next couple gun purchases.