PhysDoc,
My thoughts on S Man are not based on Petrov’s work as hadn’t read his work until after I saw his collection at Amoskeag.
When I first saw the S Man rifle it reminded me of two rifles I briefly saw in a collection in Lake Forest, IL about 20 years earlier. The owner stated that they had been redone by the Marshall Fields shop.
When I mentioned it to gasgunner he said Petrov had thought that S Man may have been in the Chicago/Milwaukee area.