It is interesting to note that the 38 s&W was essentially S&W's competition to the 38 long colt. The British chose the 38 s&W the US chose the long colt. If it was not for the British and all the lend-lease revolvers made in the US the cartridge would have died decades earlier.
Even S&W knew this. The 38 S&W Special is an improvement of the Long Colt not the 38 S&W.