The .357 case was developed from the .38 Special. Is a common myth and it almost has some merit and truth to it. But actually the .357 case was developed from the .38-44 cartridge. Now there may be some smart guys in here that will say that they are the same case. But would you say that the .38 Super is the same cartridge as the .38 acp? No but they share the same case.
The 38-44 cartridge was developed from the .38 Special and chambered in only the big N frame S&W pistols. But people being people, some tried to shoot the high velocity 38-44 cartridge in the light little J and K frame guns simple because it would fit. And it promptly blew their gun up. Another part of this myth is that Elmer Keith helped develope the .357 round. No. he did develope the 38-44 load but the .357 was Daniel Wesson's baby from the begining. He wanted a round that could be fired only in his big N frame guns and He did not want anyone getting hurt by shooting the 38-44 in his light .38 Spl. guns. (from what I understand Lawyers were not invented yet) So he decided to lengthen the 38-44 case so it could not be used in the smaller guns. And because he had his big N frame pistol all ready he decided to use all the possible length that it allowed and made the case .10 longer. Now the case would not chamber because the shoulder in the .38 spl cylinders would stop it. And if it was put in a gun without the shoulder the bullet would stick out the end of the cylinder and keep the cylinder from closing. Good thinking on his part and a good market ploy calling it a MAGNUM. And the legend begain.