Questor,
Be careful of your sources. Make sure you are using the exact components that are used in your specs and fire them from a 357 magnum first if you can. The SAAMI maximum for 38 Special is only 17000 PSI. The last I researched SAAMI did not have a standard pressure for the +P rounds in 38 Special and depending on who the manual is made by, you can get between 18,500 and 20000 PSI. The higher pressure is well over the halfway point in the pressure of the 357 Magnum. That is getting into dangerous territory for the lighter framed 38's.
Different bullets can be the difference between ok and way too much pressure. You probably have as much experience as I do and don't need me to warn you - it is just a hangup of mine. I like to see shooters and reloaders die of old age.