Of one was planning for the end of the world as we know it, wouldn’t ammo be an excellent item to trade? Assuming you trust the fellow you trade with.
Absolutely, ammo would be a primo barter item, as would be tobacco, fire water, spices, etc. But buy the mainstream rounds: 22, 9mm, 45, 223, AK 7.62, 308, 50 cal, etc., not the oddball stuff.