I searched this site and found that others were able to use their .38/.357 dies for the .357 Maximum after making the proper adjustments. In some cases using a flat washer as a spacer. I had no such luck with my dies using any combination. I checked a few new die sets at the shop and saw that they are labeled to be used for .38/.357/.357 Max. The sets included a flat washer. I came close to purchasing a Lee universal decapping die but felt that if RCBS included a spacer, then there must be someway to it. Unfortunately I was unable to figure it out.
So, today I contacted RCBS to discuss my dilemma and hopefully find out what I was doing wrong. I spoke to a very nice lady who was extremely helpful and kind. I explained to her my situation and, at her request, provided information printed on each die from my set. Without hesitation she told me that after 1981 the decapping and case belling operations were switched to different die bodies. The decapping is now done through the sizing process and the case flaring through what used the be the decapping/flaring die. Each of my .38/.357 die sets is dated prior to 1981.
Before I could comment, she asked for my mailing address and told me she would send the necessary parts needed to "modernize" my current die set. When I offered to pay for the parts, she politely said there was to be no charge and to have a nice day. I will have a very nice day, indeed.