Originally Posted by
Rex G
Ballistically, I would think it should amount to the same thing, assuming velocity is similar, with equal bullet construction and weight. (An example is the Speer Short Barrel Gold Dots.) If shooting large quantities of ammo, well, afterward, it is much easier to clean the chambers when only .357 has been fired. That nasty ring of crud that builds up at the very front of .357 chamber, when shooting .38 Special, is not fun to clean, and until really thoroughly scrubbed, can prevent .357 ammo from entering the chamber completely. I used to largely train with separate revolvers, of the same/similar models, rather than foul my .357 street guns with heavy training. (With one wrist already ailing, nowadays, I mostly just shoot .22 LR, with my S&W Model 17, anyway.)
I have read accounts of hot .38 +P eroding the chambers just ahead of the case, so that when .357 is later fired, the longer brass fire-forms into the eroded areas, causing difficulties with extraction. I cannot cite any source, as that was so very long ago, but to err on the side of caution, have normally shot either .357, or standard-pressure .38, in my .357 revolvers.