Hello Having a issue with a RRB No5 I just got. The barrel I believe cannot be saved. Ive tried cleaning etc but the corrosion is just too much. So I was thinking of reboring to 45-70? But I have been searching for a barrel also with no luck. Ive found a No1 barrel but do not know if they are interchangeable. Any suggestions on what project I should go with? I would like to keep original as the rest of the rifle is in good shape.Reboring contacts. I am in Illinois.