I'm no fan of PM investing, but as a doomsday currency there's some credibility to using gold. A good currency must be easily recognized/assessed and difficult to counterfeit. In the case of gold bullion it's assessed by weight, and I believe it's easy to learn how to distinguish gold from, say, brass or something gold plated. This may be why historically we've always considered gold to be valuable, even in eras when it had no practical use (before electronics).
Bullets, on the other hand, might be easier to counterfeit; you don't know if it's a good bullet loaded with powder until you destroy its utility (either by disassembling the shell or by firing it).
Check this out for an example of how Tide has become an underground currency in drug markets: https://www.schneier.com/blog/archives/2013/02/tide_becomes_dr.html
I'm curious, are you guys actually keeping physical precious metals in your house or a nearby bank's safety deposit box? How do you protect against theft, and have you done a comparative risk analysis of getting robbed vs. the economy crashing?