My great grandfathers shotgun

Question
Hi Mr. Gage,

I am looking at my great granfathers shotgun and I know that it is a iver johnson champion 12ga shotgun but I do not know they year or really anything else about it. The pat. number is APR 2'01 APR 15'02 and when i broke it down the serial number is 55620. Also on the but stock plate it says champion in fancy scroll like letters. I need help dating the gun and finding out more information on the gun because I do not know much about the shotgun.

Answer
Hello Jack.
  There are two possibilities for deciding the model of your shotgun and the approximate date. Since these models are not dated according to serial numbers, there is one distinguishing feature between the two. The first possible model is the Iver Johnson Champion Top Snap New Model manufactured from 1900 to 1908. It features a top lever opening mechanism with barrel lengths of 28", 30", and 32". It has automatic extractors, a rebounding hammer; American Black Walnut butt stock and fore-end; case hardened frame and browned barrel; it has a pistol grip capped with a hard rubber medallion and a hard rubber butt plate, such as you describe.
  The second possible model is the Iver Johnson Champion Model 36 which was manufactured from 1909- 1957. There are two distinguishing features on this model that were not available on the earlier one. One feature that was offered, not only the automatic extractor, but also the automatic ejector. An automatic extractor works by backing the shells out of the chamber when opening the shotgun. The automatic ejector works by spring load, thus popping the shells out when the shotgun is opened. The second feature not offered on the earlier model was the barrel and lug, the part under the barrel that holds it to the frame, were forged as one piece.
  There is, also one more piece of information that can narrow the year of manufacture for the Model 36. The name stamped on the receiver was changed from simply 'Champion', to 'Champion Single Barrel Shotgun' in 1923. Either model will only shoot the low to medium brass 2.75" shotshells.
  I hope this helps answer your questions, and thank you for asking for me. Charles Gage