Some barrels have come and gone and come again.
Call one of the larger Blaser dealers and they can tell you more about what's available with and without special order.
Used barrels show up from time to time on eBay, Gunbroker, etc., as well, but they are fairly rare.
Blaser also has a few barrels that were produced for a certain geography and only show up somewhere else because of private sales or importing. (Example: 300 WSM isn't offered in the R8 in the US due to patent/trademark issues.)
