Tim, I doubt that we will ever fit a transmitter into a 9 oz. bolt, but Ex 49'er had an interesting idea about using depleted uranium which could be found easily by using a geiger counter and Mike even has a geiger counter! However, because of where I once worked, I know a little about depleted uranium. It's pretty nasty stuff and a machinist I knew, who turned some of the first 30mm rounds for A-10's GAU Gatling Gun told me it was spooky stuff and it would hiss and crackle as you withdrew a 5 foot pc. of round stock off the metal shelving. He said you DID NOT want your lathe bit to even do one rotation without a full flood of coolant cascading over the lathe bit and the work. The phosphor effect was something you wanted to see in an A-10 gun camera film, NOT two feet in front of you on your lathe!! Frank, you might be correct; wouldn't it be fun to be there when they find those rusty old bolts. Maybe a full-fledged archaeological dig would be initiated?
We will continue with the visual method of finding these bolts, I think. Forgot to mention that Gary found one of his GB, steel balls fired from his Dom built Confederate Parrott way out at 800 yards, a real hobby-horse cannon ball with all those ricochets. The snow is almost gone, our excuses for not going shooting are dwindling. It's the temps have been so low, not a day above 50 in months. I will try to pry Mike out of the nice warm shop on the next over 46 deg. day.
Tracy and Mike