Hi
No problem... 38 spec., or 357 mag., Just if you shoot a bunch of 38's, you could get a carbon build up in the chamber. Then if you shoot a Max. you could get a pressure problem because of tighter chamber. Just clean the chamber before you shoot a maximum after the shorter rounds. You can do the same thing with 22 shorts, longs, and long rifles. But not the 22 mag. It has bigger in diameter.
jim