As Long_Gun_Dallas says, the barrel housing is the same for all calibers from .177 to .30, for the Dreamline, Wildcat, Maverick and Impact. However, while original Dreamline shrouded barrels will fit the Crown, the new SuperLight barrels on the Crown (and some Dreamlines) do not use a barrel housing and are therefore not perfectly interchangeable. (Actually shrouded SuperLight Crown barrels will fit a Dreamline, but not vice versa)
Chris