I know what you mean.  At my age, I can't shoot a decent group anymore without a scope. The classifieds section associated with this forum has a source for scope rails, but I investigated their 3 inch rail, and found that I would need to cut some wood from the top of my model 1898.  However, not all 1898s are the same. I understand that some early 1898s had a rear sight from the 1896 model.  The wood might be cut differently to accommodate that difference. It might be possible that the top wood on yours could handle a 3 inch scope rail without any cutting.  On the other hand, if you don't mind drilling, their 6 inch rail might be good.