Although it would be correct to say the .38 S&W is obsolete, they continued to make revolvers in that caliber even after WWII, probably into the 1970s, as did Colt. Colt had this habit of renaming cartridges, so there is a cartridge they called the .38 New Police as well as the .38 Colt Special. Some Ruger Security Sixes were also made in that chambering, presumably for sale in British Commonwealth countries. It was the British service cartridge until finally replaced by the 9mm.
I know I mention this every time the subject comes up but an old US Army manual I have refers to the cartridge as the .38 Regular, which I suppose is a very logical name.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
Buy War Bonds.