http://rifleactions.com/

Look at the above link too see the Hein SA.
If you were building a rig like this (with 3"box) Tell us, what cartridge you would choose?
Personally I would like the 6.5x54MS.

Or am I mistaken, Is this their 2.5"box action??

That particular action is reminiscent of the Kurz Mauser so I guess I'd go with a 250-3000.

250-3000.

Dave