You will get all of the predictable replies about how stainless will rust, it just takes longer, etc.
I am assuming you acquired the revolver new, and therefore can say with certainty that no prior owner did anything stupid like file on the trigger guard, use steel wool or bleed all over it.
Assuming normal use (i.e. - it was not dropped in the ocean or stored there for an extended period, or you didn't leave it packed in salt under your outdoor sprinkler for a few days), then the problem might very well be that it did not go through the passivation process or it did not go properly through the passivation process at S&W after machining.
In general terms, the passivation process is used to remove carbon or iron material contaminants from stainless steel after machining or manufacturing as the cutting tools are carbon or other material that will rust and the machining process leaves microscopic bits embedded in the stainless, and it those bits that rust, creating the brown pitted effect.
I have seen new stainless revolvers develop the characteristic brown pitted-looking surface within two weeks of receipt from the distributor and in each case, it was a failure to properly passivate the revolver. Oddly, in every case, the reddish brown "pits" did not appear all over the revolvers, but only on certain parts - top strap, sideplate, etc. S&W confirmed in each case after the new revolvers were sent back that they were not properly passivated. S&W took care of each case in short order, with no further owner problems upon return.
Naturally, this is one reason the end user should really never use steel wool as it leaves contaminants in the same manner, which can require re-passivation. Knowing this, people just keep on doing it, making sure to use enough oil to make a middle eastern oil Sheik blush in the process of trying to correct or control the rusting effect after the ill-advised use of the steel wool. Oh well.
With all due respect to the previous post, if a stainless revolver needs paste wax to keep from rusting (given normal use and care - i.e. wipe it off and keep a very thin coat of oil), then you have a big problem with the finish and the revolver needs to go back.
My suggestion: what you describe shouldn't happen and it needs to go back to the factory for evaluation and correction.
