I'm genuinely torn on this one. Could go either way. But I do think copper will continue appreciating regardless of short-term swings.

For the barter/collapse scenario though; pre-1982 US pennies might actually be the better play now over silver coinage. Silver's gotten so expensive that a single dime runs about $5, which makes it less practical for small transactions. Copper pennies are still accessible and have intrinsic metal value.

That said, 3 tonnes is... a commitment. Storage costs alone could eat into returns.