I want to let you gun builders know that I do still have both 12 gauge rifled tubes and some 20 gauge rifled tubes that will work on a 12 gauge to 20 gauge rifled conversion. I also have a few of the machined one piece top ribs for sale at $100.00 each. The 12 gauge rifled barrels are made by E.R. Shaw and are $100.00 each plus shipping. The 20 gauge rifled barrels are from Verney Carron and are normally $150 each but I will sell you a pair of them for $250 a pair plus shipping.
These Verney Carron barrel blanks are bull barrels of 1 1/4 inch thick and 30 inches long. They are the smoothest and best finished barrels I have ever used.