I had to go back and check my sources. In Lyman's GUIDE to BIG GAME CARTRIDGES & RIFLES Ed Matunas states that the then new Ruger 77 Mk.II Magnum(RSM) is chambered in the above referenced calibers. So it appears I was in error and that it was the RSM to which I was referring. On that same note I have seen one Ruger .404 on one of the auction sites (Gunbroker?) a few years ago. I honestly don't know if this was a legit factory rifle or one someone was trying to pass off as factory.

Geronimo