0000 Steel Wool will scratch the HIGHLY polished S&W models. So will bronze and copper brushes.
You might have to use a magnifyer to see them well, but they are there.
0000 Steel Wool does not noticeably scratch satin finished guns and guns with a lower degree of polish like the inexpensive 22 rifles.
Bronze Wool in the finest grade available from Brownell's is the thing to use- WITH a good oil.
CorrosionX is the finest product for dissolving rust that I have found, and I have tried most of them. It is noticeably better than Break-Free and Wd-40, which are both good.
Give it time to work- days if necessary. Also keep the gun warm while it is working.