If memory serves correctly, all Purbaughs used their own extractors, I don't remember them using the extractors as part of the tube chamber,like Briley or Kolar. So these may not be Purbaughs, unless it has a special extractor that works with the 20 ga rims cuts. Another thing to keep in mind, with the attached extractor guns, and I don't know about Purbaughs, is that a lot of the manufactures of the tubes cut a long forcing cone in the original barrels to get a beefier chamber on their tubes, to take care of pressures. I don't know if this long forcing cone would be desirable in a twist or damascus gun for use without the tubes. But, it does sound like a nice gun, and would be a pleasure with low pressure loads.
