Probably a worthless response since I have no experience with J&J, but I do have a 14" DW Fibur, with the freak inserts. It's as accurate as any barrel I've shot with, and is very quiet. My next step is to grab some brass inserts to try... Anyway, the DW is a solid product.
To die for an idea; it is unquestionably noble. But how much nobler it would be if men died for ideas that were true?- H.L. Mencken