I think I've seen statements about Mike Brooks (or maybe someone else?) dragging a finished rifle behind a car in a gravel driveway. I don't know if that's true .... But maybe.
My thoughts had always been that the rifle is well finished, as new, then had various scary treatments applied. Dragging through gravel, buried in the dirt in summer and watered for weeks, hung over a wood stove or put in a kiln, repeat all that multiple times, take a high RPM buffing wheel to various spots. Refinished, etc.