The idea of survival is an old one. I remember reading an article back in the 1950s by “Perry Mason” author, Erle Stanley Gardiner.
The only thing I can remember was his saying one should have an accurate long barreled .22 Revolver or Auto along with ammo. I personally think a .22 rifle would be even better and of course have a spare.
Also powerful airguns simply because ammo would be so easy to stockpile. Not for defense but for hunting. I think someone with some knowledge of the scenario said that game would be hunted out very quickly. Fish would be gone nearly as soon.
be pretty hard to hunt down all the game, at least here in Canada, heck there’s 14 million geese alone, factor in reproduction and I think there will be some animals around for quite some time. The population would have a drastic thinning out in a hurry which would increase the animal odds.