Well I'd hate to shoot my Colt Police Positive .38 S&W (Chase Manhattan Bank stamped) with a handload but...
Now this is for a swing out cylinder revolver of modern steel. Not a top break. And start low and work your way up.
A 148 grain HBWC and 2.5 grains of Bullseye works well. You can actually load it a bit 'hotter'.
And no I don't reverse the bullet to make some kind of manstopper load. The wadcutter itself is actually a good SD load.
Almost like a .38 Special match load!
Do note.. if you want to make it a .38 Special +p.. buy one. These old guns are not to be revved up to something they are not.