Thanks for all the great replies, guys!
mr. potatoethrower (9,3x57): You are right on the spot about norwegian moose beeing the main game I will hunt with this rifle, and maybe the occational deer and even a brown bear in a lifetime, if I'm lucky

While I'm aware that many Mausers of old where "africa-models", made with 28" barrels, I have also seen some original Oberndorf Mausers with 24" tubes, and some even bulidt on a small-ring action, like my Brno

I have been thinking that with modern powers I should be able to have this round chambered in a shorter barrel, like 20", and still get the original velocity of 2150fps with a 347-350grain bullet, or maybe even up to 2300fps.
I would also like to try 400grain bullets my gun, and if anyone has got experience with this bulletweight, and what velocities you get from different barrellengths I would really appreciate that aswell.

The rifle will be buildt in a modern-classic style, with a straight comb made to fit with a low power scope, and a peep sight for back-up. And of course a sling swivel on a barrelband

Thanks for all your help so far.