Wasn't the Mannlicher Schoenauer the one with the slick rotary mag?
Yes, and Rhiner is 'way off base on the bolt, too. This is a straight - pull action!
The Mannlicher-Schoenauer has a normal turning bolt, like a Mauser or Enfield in that regard. The Greeks adopted it in 1903, but it's much better known for use in sporting rifles and full-stocked (stutzen) carbines. They may have single or double-set triggers. Most have flat bolt handles.
The M-S M-1908 sporting arms were in caliber 8X56mm Mannlicher-Schoenaur. (Rimless. Looks a lot like 8X57mm Mauser.) I had one, and loved it. But ammo was hard to find. Speer imported some from DWM years ago, but not lately. I also got a box of Western brand US-loaded ammo from the 1930's. It's a weaker-loaded round than modern 8x57mmS Mauser ammo.
The rifle shown is probably chambered for some other ctg.
with a rim. It looks like a German or Austrian custom gunsmith made it, probably between WWI and WW II.
You'll need a chamber cast and a copy of, "Cartridges of the World." No telling which round it takes.
It might be a "German boar-hunting rifle." Or a German rehbok (roe deer) or red deer, etc. rifle...depending on what was being hunted that day. Maybe chamois in the Alps. Maybe a fox. You get the idea. "German boar-hunting rifle" is just gun show sales hype by an ignoramus who doesn't know what it is.
The action was probably made by Waffenfabrik Steyr.
The rotary magazine on the quite different M-S rifles was designed by Otto Schoenauer. The other designer was Ferdinand Ritter von Mannlicher. I'm sure you can find him on Wiki, etc. He was a major rival of Mauser.
Mannlicher military rifles were used by Austria-Hungary, Holland, Romania, etc.