Buy ammo for long term storage. Period.
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1. Factory ammo is a currency. Reloaded ammo is not.
Reloaded ammo *Might* be a currency in some apocalyptic future, but right now it's just stored.
As your situation changes, you may need cash more than ammo.
Reloaded ammo won't sell for the component price, if you can find anyone to buy generic reloaded ammo at all... I won't buy generic reloaded ammo unless I want the bullets, cases & maybe primers and I would break any generic reloaded ammo.
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2. You just don't dig a hole and dump ammo in it for later...
YOU serve anything sitting around, secure storage, cool-dry storage.
You pay taxes or rent, you pay insurance, you pay upkeep on the storage.
People buy this stuff, but don't think about ammo cans, safes, climate control, etc.
If it doesn't do something to serve YOU... YOU serve it.
3. IF THERE WERE an 'End Of The World' event... (And that's a HUGE *IF*)
You have to consider HOW you will move thousands of rounds of ammo.
Dig in, and you are a stationary target.
Move, and you have to consider lodgistics. The average battle load out is 300 rounds simply because of weight. Ounces equal pounds and pounds equal pain.
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As for what specific bullet, a soft point, no question.
Hollows destroy small game and fragment in large game.
FMJ isn't the best choice for hunting.
*IF* I we're going to stockpile for some apocalyptic future, I would buy a viriety of bullet types, it's not like you aren't going to have several storage cans, so this one hollow, that one FMJ, the next soft point, etc.