FWIW, since I almost always have a Glock strapped to me my in-BoB survival gun is a .22 conversion kit for the glock. While the kits aren't especially cheap, they aren't guns themselves so they have fewer security issues, and provide me the option of having a major caliber defensive weapon and a 'survival' caliber. I do the same thing with an AR conversion kit.
Emergency Medicine - saving the world from themselves, one at a time. "Thou shalt not be a victim, thou shalt not be a perpetrator, but, above all, thou shalt not be a bystander." I make the ADL soil themselves. And that makes me very happy 
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