I am poking my toe into the world of amateur gunsmithing and have promptly hit upon a machining question. It concerns Jeweling, specifically jeweling a rifle bolt. The how to is simple enough. I could build the jig and execute the process with little difficulty. The question in my mind is "Why?". What benefit (other than the cool appearance) is to be derive from milling this pattern into the surface of the bolt (or, for that matter, any other surface).