I would certainly recommend a 9.3x74R. It's a great caliber for anything you mentioned. Various choices are out there in a new product, and there are lots of vintage rifles to choose from. A QD scope is good to have on this rifle.

There's a pretty nice .400/.350 HERE. Trouble is, with that chambering you would be taking on a load of misery. Also, if it has true 9mm barrels you are in trouble with bullets. If the bores are .358" no problem with bullets. This rifle is at the top of the chart on pricing IMO.

A good 8x57JRS is no slouch. Not quite as popular, but a great round with plenty of bullets available. Hallowell has a Chapuis in that chamber.

The 9.3x74R is universally available.

Curl