What is meant by relining a barrel? I gather that smiths put a metal tube inside the original barrel. Other than that I don't know much about it. Is it expensive? The only reason I asked is because my old Winchester 150 is not shooting like it used to. Used to hit dead on at 25 plus yards. now the shots are printing all over the place. I clean the gun every time I'm done using it. I can't tell if the rifling is bad or not. I know I'm getting old and the hands shake a bit but not that much. Thanks in advance.