An oldie - A S&W Model of 1902, probably dating from around mid-1905 assuming it has a rounded butt. If square, it would be a Model of 1905. The U. S. Service CTG refers to the .38 Long Colt, although it is chambered for the .38 Special. The .38 LC is just a little shorter than the .38 Special, and is essentially an obsolete cartridge today. It was an official U. S. military revolver cartridge at the time. Why don't you post a few pix?