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
One thing I noticed with my Sig 938 was the breech face had been bead blasted at the same time as the slide, as had the underside of the slide where it runs on the disconnector, and the top cartridge in the mag.
Not a true 1911, nevertheless it's an example of how "modern" sometimes unimproves proven designs
These surfaces must be smooth, or function will be sticky.
![[Linked Image]](http://i712.photobucket.com/albums/ww127/tex_n_cal/74cafcc6.jpg)
After I polished the affected surfaces, the little Sig ran fine, where it had been jamming.
