You have bought the finest, IMNSHO, .357 revolver ever built. As above, no sane factory loaded round will damage it. BTW, what barrel length is it?

My favorite holster is the lined Model 29 made by Safariland. Not sure they make them anymore, but I'll bought several off of eBay. Look for ones marked S&W LG FR (large frame). Make sure you buy a leather holster. Safariland started making holsters out of some sort of synthetic a while back and they don't hold up as well as real old fashioned cowhide.

__________________
John 3:16
WAR EAGLE!