Yep, it's a 8X57IS (.323" bore). I doubt that Husqvarna ever made a .318" barrel. The 8X57I has a neck diameter of 8.99mm (.3539"). I have verified that my Husky has a 9.09mm (.3578")neck. No problem in that regard.

The same problem crops up with trying to rechamber a 7X57 to 7X64, but the difference in neck sizes is greater: 8.23mm (.3240")vs. 7.95 (.3129").