Carl,
Have you removed the barrel from the rolling block? If so, what is the major diameter of the threads? What is the major diameter of the Winchester thread? Due to the difference in head diameter between the two cartridges there is a possibility that the Winchester threads can be turned off and the shank re-threaded for the rolling block thread. However, for the same reason, doing that may very well result in a barrel shank too small for the 25-35. You may find it necessary to cut the chamber portion of the Winchester barrel off and chamber it to 25-20 instead. I would recommend you sell the Winchester barrel and have the rolling block lined to 38 S&W Special and load it to 360 ballistics.
Mike
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