Not sure I quite follow the multiple suggestions to check the sizing die for differences between the length of .38 and .357.
This doesn't make sense -- when you employ a modern carbide sizing die, you run a revolver case all the way so that the top of the shell holder makes contact with the base of the sizing die.
This is the proper way to use a modern carbide sizing die with any/all pistol brass, revolver or rimless or semi-rimmed.
When you set the die up this way, which is also the way the instructions direct you to do so, it won't matter if your brass is .38, .357 or .357 Max, it's going to get sized fully.
While there absolutely is adjustment difference in your case mouth flare die and your bullet seat/crimp die between .38 and .357, there is no adjustment and no difference in your die setting for a modern carbide size die between .38 and .357.