Polishing or Not - Chambers?

[Larryjk]

Don't get too many variables into this discussion. It was originally about "highly" polished chambers vs those made with a reamer in good shop procedures. I had proposed that a "reamer run" chamber was the most practical because the case expands in all directions under the pressure of firing (between 55k and 65k lbs./sq. in.) and is held in place by the friction between the chamber walls and the brass case. If there is no friction (as in a highly polished chamber) all of the pressure results in more bolt thrust.
If you look into a good "reamer run" chamber before the barrel is blued you will see how nice and shiny the chamber is. But if your procedure left scratches in the chamber, you will need to polish out the "rings", or set the barrel back a thread or two and recut the chamber using better cleeaning techniques. Yes, all chambers can rust if not attended to, and in my experience some calibers more than others. But that may be due to some calibers being used under more adverse conditions rather than a factor solely of the caliber.