I reload the .38 spl with black powder and a (nominally)158 grain bullet. Modern cases are obviously made with thicker brass since it's a struggle to load even 21 grains, and still get a tiny amount of bullet creep. In .357 cases 21.5 grains of 3F black work just fine. I was truly amazed at the accuracy of these loads at 25 yards. A lot of smoke, concussion and fire; in other words, FUN.