Iver Johnson 12 ga. shotgun

Question

Iver Johnson 12 ga.   QUESTION: I have my grandfathers Iver Johnson 12 ga. single shot and I'm trying to figure out how old it is.It has a 32" barrel, breakdown from top behind hammer, top of barrel it reads Iver Johnson, end of butt stock it has Iver Johnson written but nothing else. Also behind the trigger there is a screw that adjusts how far back the hammer goes and trigger pressure. I found some numbers on the under side of barrel where it locks together and they are 51323. I can see part of some numbers on the side of the case, but stock covers part of it and can't read without removing the stock. Looks to be like a nickle color where the hammer is, barrel is blue. No one in my family can remember him buying the gun or if someone gave him the gun. Thank you for any information you could give. I'm not getting rid of the gun, just trying to find some history on the gun.

ANSWER: Hello Bobby.
  Your Grandfather's shotgun is an Iver Johnson Jacketed Breech Single Gun. It was manufactured from 1912 to 1917. It was one of the Champion series that Iver Johnson manufactured from 1909-1957. The hammer and receiver were nickle plated when new. It looks as though there has been a severe rust problem. If you are planning to shoot it, I recommend you have it checked by a licensed gunsmith.
  Thank you for posting the picture. In all my research, this is the first of this model I have seen. I knew of it, but as for the set screw, I have never read of it.
  I hope this helps answer your question, and thank you for asking for me. Charles Gage

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QUESTION: Do you have any idea of it's value. As far as the rust, it looks like it in the picture but it has no rust. Thanks again for your help.

Answer
Hello Bobby.
  Although your shotgun is around 100 years old, the Iver Johnson Company made over a million shotguns over their history. These were low priced, but good quality shotguns, for the common shooter. They have never reached collector status, so the value today is only as shooters, around $100. Hope this helps, and thank you again for asking for me. Charles Gage