They are 100% bullets. They may not be that old either. I have reloaded for many years and I have some components that look identical to those. Not having a boat tail doesn't do anything to determine age. I actually prefer a flat based bullet, they are more accurate than boat tails out of my rifles. By the photos it's hard to judge size but I am guessing 30 cal or smaller. This includes a large amount of hunting rifles that are capable of shooting a caliber in this range. It is obvious the bullets didn't strike a solid back stop as they aren't deformed at all. So the source could have been miles away from where they were found. I was detecting out behind the house yesterday and found a few Hollow Base Wad Cutters in 38/357, I haven't loaded those since 94 and I am sure it is one of mine. That's what you call recycling, lol!!!