I found an actual round minus primer and powder at the gun show so I just got that. $3.
I had walked through most of the gun show without finding anyone selling just the bullets which I thought odd but I came across this guy that had four of them with the original tips in. I asked if these were the ones that could explode and he said yes, don't let your kids play with them. They won't go off easily, in fact they look designed to prevent it from happening. The tip is a little cone with the solid dip down inside this protective cone. Probably so they can be handled safely but obviously impact upon firing would set it off.