So I stopped by my local machine shop today to get a quote on having my 781's rebuilt. My machinist told me that replacing the cast guides is his last resort and that he would rather install bronze guide liners. When I told him that several of my factory guides were chipped or broken he told me I would be better off finding a better set of cores to start with. Is replacing the cast guides that much of a pain or should I be looking for another machine shop?