I've used Starline .38 Super Comp cases for years. I've found them to be very sturdy, durable cases, even when loaded to 9X23 Win. levels. FWIW, I've loaded 9X23 Win. too. The 9X23 brass was designed to be used in traditional Colt type non-ramped barrels, that do not have case heads as well supported as the ramped barrels used by other manufacturers now days. The very beefy 9X23 Win. case heads provide a margin of safety in the non-ramped barrels, but the heavy case does have reduced powder capacity as compared with .38 Super/Super Comp and similar brass. It occurs to me that 9X23 Win. level loads developed in the .38 Super/Super Comp type brass likely produce less pressure than factory 9X23 ammunition due to having greater case capacity than 9X23 brass. In any case, I've not experienced any issues in loading modern .38 Super/38 Super Comp/36TJ brass to 9X23 Win. levels in my guns with well supported integral ramp type barrels. I would not have attempted this with the standard Colt barrels and vintage/thin case head .38 Super brass I started with back in the '70s.
I've attached a photo I attribute to Brad Miller on his old .38Super.net site showing sectioned 38 Super type cases.
