One of the SWC Keith type bullets has the same case volume when loaded in either a 38 sp case or 357 case. In 38 cases, crimp is below top band, in 357 case, crimp is above top band.

So you can use your regular 38 sp powder and loadings in the 357 case. No carbon ring from short cases.

Bullseye and Unique are my goto powders for 38 sp.