[Austin W Hogan]

Thank you for that observation of the putty between the barrels. I have a heavy two frame barrel set and a three frame barrel set that are of identical weight. The individual barrels are the same diameter, but the three frame set makes up 1/8 inch plus wider, as it should. I calculated that the void volume between the 3 frame barrels would need 1/4 pound plus of solder to fill.
Your account of putty filling the void also supports the need for drilling a vent hole in the under rib when re bluing a barrel set.

Thank you, Austin