WHAT DOES DAN WESSON SPECIALIST MEAN?

Pistol Pacs have been designated by a “P” then the model range of the revolver frame, then the barrel shroud form (blank) for traditional, “V” for vent, “VH” for Vent HeavyHence the cylinder is definitely different.  Possibly the threading differs from model to model to keep from with the ability to interchance barrels to models?My pla