I got tired of readjusting dies when switching between .38 Special and .357 mag and considered buying another die set, but being both a cheapskate and a procrastinator I never got around to it. Then I flashed on a solution, probably an old idea but new to me. I took my digital caliper to the local True Value Hardware store and checked the thickness of a 7/8" flat washer.
Eureka it miked .135" thickness, exactly the difference between .38 and .357 case length. I adjust the dies perfectly for .38s and when loading .357 I place the flat washer under the expander and seater dies and I have a perfect setup for .357. Eighty-five cents did seem pretty steep for one steel washer but a lot cheaper than a set of dies.