The .38 Super Comp is a .38 Super without the stupid rim (unlike 9x23, that is a lengthened 9x19 with the same size head). It fits best in the .223 shell plate. Since the .38 Super, with the stupid rim, doesn't fit the 9x19 shell plate very well, the smaller head of the .38 SC will be an even poorer fit. It "might" work, until the press rips a case out of the too large shell plate...