I have a pre 29 4 screw with the serial number S 1704xx stamped on the frame at the yoke cut out. There is no model number stamping. I would expect to see the serial # stamped on the bbl at the ejector rod cut out for a gun with this serial number, preceded by a B for blue finish. I know this is in an era of "transition" stamping as they were moving away from the bbl to the yoke numbering, and were dropping the cylinder stamping as well. This one does not have a serial number on the cylinder face. It does have it stamped on the extractor.

I had a later serial number S 1813xx that was a pre 29 with the number on the bbl.



I have not seen an example marked like this. Seems odd and was just curious.

Charlie

I have a 176 marked the same way,but the cylinder is stamped too.

There is a transition period in 1957 between the 5 screw and 4 screw guns. After they quit "soft fitting" they quit numbering all of the parts. Your number should be under the extractor star and maybe on the back of the crane.

The "B" for Blue was a pre-war mark. Post war guns would have an "N" for nickel but nothing for blue.