When the American economy collapses so does the rest of the world so gold and silver will be useless. A fifth of anything will get you more bargaining wise.
The purpose for investing in precious metals is to transfer a block of wealth from now into MANY YEARS AFTER THE WORLD HAS FINISHED RECOVERING FROM TEOTWAWKI. Possession of precious metals DURING the siege is a detriment as others will vie to steal it. Precious metals are a time teleportation strategy to re-establish a degree of societal position based on level of wealth.