Some of the newer revolvers are made with a 2 piece barrel (barrel and a barrel shroud). They might be considered as beign a cousin to the way Dan Wesson barrels are. They can't be changed by the user like on a DW. The 329PD & 340PD are like that with an aluminum shroud over a steel barrel.
I've seen a very few comments on different forums about some of these 2 piece barrels breaking.
The reference to one piece barrels is probably due to this.