Can be helpful to a receiver that is really rough....here's the tool and info per Brownell's
https://www.brownells.com/gunsmith-...iver-tools/receiver-way-polisher-prod395.aspx
HOW TO USE
After the receiver has been stripped, use a good quality solvent, such as d’Solve™, to remove all traces of grease, dirt, and carbon. Carefully inspect the "ways" for cracks, unusual machine marks, roughness, etc. With the inspection complete, coat the "ways" with machinist’s layout fluid and allow to dry.
Select a suitable grit of cloth-backed abrasive. In most cases we have found that we can usually begin with a 220 or 320 grit abrasive. Cut a small strip approximately 11⁄2" by 21⁄2". Loosen the Allen head screw in the body of the Polisher, spreading the two legs of the body slightly. Insert one end of the abrasive strip 1⁄2" into this slot. Hold this with your thumb, wrap the rest of the abrasive around the body and tuck the remaining end of the strip into the slot. Tighten the Allen screw, drawing the legs of the body together and securing the abrasive cloth. Be sure the abrasive coating is facing OUT from the body of the Polisher!
Secure the receiver or barreled action in a padded vise so that you have unrestricted access to the rear opening in the receiver. Apply a few drops of stoning oil or kerosene to the receiver bolt "ways". Insert the Polisher into the rear of the receiver as you would the bolt. Make sure the flats, or bottom, of the Polisher Body contact both right and left receiver bolt "ways"evenly. Apply moderate downward pressure on the other handle and carefully move the Polisher head back and forth along the bolt "ways". If you are holding the
knurled handle in your right hand, use the left thumb and forefinger to apply additional downward pressure directly on the Polisher head.
IMPORTANT NOTE: DO NOT install the bolt or any other component in or on the receiver until you have THOROUGHLY and COMPLETELY cleaned the receiver of ALL traces of abrasive. Bits of abrasive remaining in the receiver could damage other components or cause malfunctions in critical assemblies such as the safety or trigger.
For optimum smoothness, the bolt should also be polished to remove all machine marks, or roughness. This is especially important when working with some of the older military bolt actions such as the 1903-A3 Springfield. After a few strokes, remove the Polisher and wipe off the bolt "ways". The manner in which the machinist layout fluid has been removed will give you an excellent indication of where the roughness and irregularities are located. Apply a few more drops of kerosene or stoning oil to the bolt "ways" and continue polishing. Check your work often and move to a finer grit as necessary. It is possible to polish the bolt "ways" to a mirror finish.
