SKB;
That is a piloted expansion reamer but I do not think it is designed for cutting a Jug Choke & certainly not one which could be used with one end of the tube plugged. I presume that all in this discussion does understand the difference between Jug Choking & Back Boring. An ordinary expansion reamer is normally adjusted outside the hole & used in successive steps for enlarging a hole in small increments.
In order to Jug a bbl it is necessary to do the expansion without removing the tool. A normal expansion reamer does not cut efficiently down the length of its flutes, but as it goes forward it cuts on its leading angle.
See SDH I do understand what you are saying, one doesn't just pick up a standard expansion reamer & jug a bbl with it. It does however remain as a "FACT" that enterprising folks have come up with various ways of effectively accomplishing the goal with out the removal of the breeech plug & without a large enough lathe to swing the bbl set in.
