Everyone is saying gold and silver, but without the actual metal in hand all you have is worthless paper.

Land, and equipment is going to be a better play. Ammunition is great, but ammunition and reloading equipment is even better. The ability to produce your own propellant and primers would be ideal.

If shit really hits the fan then land to grow food. Food will be used to barter. No one wants to trade scraps of paper when you have potatoes to trade - or potato vodka.