Polishing a feed ramp & the throat, chamber & barrel hood tang, given the correct felt bob & polishing compound, will not alter the geometry.
Using a grinding stone is quite another story.
Unless there is something dramatically wrong with the feed ramp and/or the barrel fit to the ramp, which is fairly rare, there is never a need to change the geometry.
And then it should surely be done by someone knowledgeable in how the fit should be; lots of bubba's in the gun owners world though.
MM
