S-man is a name assigned by Petrov in his books on Classic Rifles.
It means a maker of custom rifles that were obviously stocked by the same master gunsmith but Petrov never learned his name.
Fred might be able to link to the previous thread about the S-man. This new one showed up in WI and came from an estate so nothing new on who may have made them. The new owner will be taking it apart to see if there are any hidden clues. I now have a list of 12 '03 rifles made by the S-man. Michael had a photo list of 7 plus the nice one he owned. A TX dealer has told me he has two but so far he hasn't given me the data so I haven't listed them. There are other rifles with an S type PG but are not S-man rifles.
Dan
Here are some links to previous S-Man discussions, I am having
trouble finding some of Michael Petrov's earlier discussions.
S-Man discussion S-Man exhibit