I tried a Craterex rod process as recommended by Potterfield of Brownells, for bolt jewling, I am not impressed on a Mauser bolt. I normally use a small wire bush with two 0 rings on a steel rod with valve grinding compound, the steel rod does not flex. Too many humps, holes and cuts on a Mauser bolt for the wet noodle Craterex rod tip.
I note that Potterfield did a 700 bolt body, which is just an even surface round steel tube. If you only have a even surface the Craterex will do fine. Well learned a new lesson.