[Doc Hoy]

I am given to understand that the .775 case length is the .38 S&W.

And maybe that is a better way FOR ME to understand the differences.

I am going under this assumption:

Three case lengths:

.775 inches - .38 (I am given to understand that this is referred to as .38 S&W)

1.290 - .357 when referring to a smokeless round

1.155 - .38 special, also referred to as Long Colt

When I say, "when loaded with black powder" I mean, in the present day, loaded for CAS (even though I don't shoot CAS) and not what the cartridge was originally designed for. The question might be better posed; "What to CAS shooters call their rounds? If you have a revolver that is .38/.357, and you are loading black powder rounds, do you call it a .38 round, a .357 round, a .38 Special round, and if so, what is the difference?

Here is why I ask:

If I move into the .38/.357 caliber, I would probably stay away from .775 cases because of the limitation on the powder. I load only black powder, never smokeless.

So this means I can choose between (IIUC) two different case lengths. 1.155 and 1.290. In this case, the difference is minor and so I would likely go with the larger of the two sizes for flexability. It is important because if I am working with two different case lengths which are really only different by about an eighth of an inch, I have to reset my dies. So I wuld likely stick with one and only one case size.