My son wanted a larger caliber rifle for Christmas and I found this gem for the right price. I saw that it was a quality "lifetime" gun and figured I'd start my son out with a gun he won't outgrow since he was bragging that the recoil on the family .243 is no big thing and he was ready for more punch. The question remains, what the heck is it? It's a German Mauser. It is modern. (made post-1968) It doesn't look like a large ring as best as I can measure, and it doesn't look like a "traditional" single or double square bridge action either. I've found no other example to compare it to online in the modern era Mauser department. Some sort of one-off run of square bridge non-magnum actions? There is more material present on the receiver than would be possible if you just milled down a large ring it seems, and the bridges don't look welded up to me. It takes a side pivot mount from the front saddle, and then locks to the rear bridge dovetail. Thanks for giving your opinions on this strange made-for-European-Market oddity.