I have to wonder if the nomenclature is getting mixed up on their forum?
A fouling ring at the mouth of a shorter case is NOT chamber ringing. A properly maintained arm will not have this issue.
I have followed actual chamber ringing for some years and it can be accomplished with the proper case for the arm, as well as shorter cases, by using an over powder wad (to hold a small amount of fast burning powder back to the primer), or shooting straight up. This has been repeated and documented (see, The Modern Schuetzen Rifle by Schwartz and Dell, among other articles).
The ring, an indenting around the chamber, right at the base of the bullet will be pounded in, and may not be noticed until extraction becomes difficult. It is the chamber version of a barrel bulge.
There is often no fix without setting a barrel back, relining or , at least, lining the chamber; all heavy in precision machining and cost. Sometimes an oversize cartridge rechambering can salvage the barrel.
As you can see, there is cause for concern, but with what I understand, there is no reason using 38s in a 357, etc. will do this UNLESS they used over powder wads or did a bunch of sky shots.
