So these may not be Purbaughs, unless it has a special extractor that works with the 20 ga rims cuts.
I don't have any pics of this gun (yet), but the extractors don't resemble anything I have seen on a Google search of Purbaugh pics.
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.
I suspect that may be the case, but I can't tell without removing the inserts. That's why I want to mic the chambers at the breach end to see if they were machined to accept the chamber sleeves. If they are larger than standard 12 ga dimensions, then I guess the inserts and sleeves have to stay.
Another thought is that, if I can get the barrel sleeves out without damage and if the original barrels pass inspection, I could leave the current chamber inserts in the gun (cut off the barrel sleeves) and use 20 ga shells. This should lighten the gun considerably. Or, I could possibly use Chamber Mates or Gauge Mates in 12/16 or 12/20, although my preference would be to just go with low pressure 12's.
