Smith & Wesson introduced the 38 Special about 1899 for use in new S&W revolvers. With a longer case, it had a ballistic advantage over the 38 Short and Long Colt rounds and the 38 Smith &Wesson (a shorter round S&W introduced in 1877 that is very similar but not interchangeable). As far as I can determine the 38 Special was never factory loaded with blackpowder. The bulky blackpowder substitutes of the era required similar case capacity to duplicate blackpowder performance and this seems to have been one reason Smith & Wesson lengthened the 38 Long Colt case to make this newer round. One reason for doing this was to assure this round could not be used in older 38-caliber cartridge revolvers. Doing so with the higher working pressure would have been dangerous and likely would have destroyed the guns. High-performance factory 38 Special ammunition and handloads using the 38 Spc case intended for use only in the large-frame 38-44 Smith & Wesson revolver led to the 1935 introduction of the longer 357 Magnum, again, mostly to create a cartridge that could not be used in older, weaker guns. As with any revolver round, best practice is to apply a roll-crimp after seating the bullet. This helps to lock the bullet in place against chambering forces that might otherwise drive it into the case. I cannot too-strongly recommend getting a second seating-and-crimping die so you can have one adjusted to only seat the bullet and the second adjusted to only crimp the case mouth. Generally, attempting to do both operations in one step is a recipe for damaged and destroyed cases.