I have a Hand ejector S/N 578785 (no letter) 38 cal. 3 1/8 inch barrel with fixed sights. It has a strain screw and 5 screws in frame. Thanks for any info on this revolver.
Are you sure about the barrel length? Measurement is made from the front face of the cylinder to the muzzle. Is the caliber .38 S&W or .38 S&W Special? That should be stamped on the barrel. Pictures always help.
I'd guess you have a Military and Police (M&P) from about 1927-28.