Interesting,since a"plugged nickel" is a nickel with a hole in it and the hole replaced with cheaper metal. Now we are down to a worth of less than five cents, instead of $1750. And, the 21 was a hardware store gun.So, my estimate of rebuild is a bit off. How about getting the gun, $.04,rebuilding, and selling for: $7500 minus $1750 = $5750 + $.04 = $5750.04?