This is a set of Briley Subgauge tubes They were in my K80 they are companion tubes 30" long, and they are straight rifled, ultralight. Currently, they have skeet chokes and I think I have one IC for each gauge ( total of 3 xtra chokes). They will ship in the Briley Extruded plastic case. I have the hammer, and knock out also. They are in really nice shape. PM with any questions 1250 shipped punch
The external bore of the tubes is .724. the bore on the insert, that goes into the barrel is .805 the plastic grommet that Briley uses to snug the "chamber" part of the subgauge tube into the chamber was replaced with a brass insert, see pic, and that adds .010 or a total of .815 to the receiver end of the barrel, it the makes sense, see pics barrels have screw in skeet chokes