Hi folks, first time poster here!

I recently acquired a beautiful old sporting Mauser in 9x57 & I'm trying to research a little of it's history.
So far I've ascertained that it is indeed a '98 large ring action & that the load range data on the side of the front ring dates it to pre 1901. My best guess at an age range is 1899-1901.

It was rebored (or possibly rebarreled) from 7.92mm at a later date & the Suhl 'Crown over N' proof mark leads me to believe that this work was done post 1950?

There is a signature inscribed on the bottom flat of the barrel, beneath the stock & I think it reads "Shüler" then possibly Karl or Kurt (my German cursive is't what it used to be....) & I'm assuming by it's comparatively crude nature, it's an owner & not a gunsmith.

There are a bunch of what seem to be random letters, numbers, possibly a word & possibly other proof marks under the action & behind the recoil lug & a recurring serial number on all metal parts (except, oddly, the magazine box, floorplate & trigger housing)

I would assume the original makers marks, factory or possibly Imperial markings would've been on top of the front ring & lost during the dovetail cut for a scope mount

I was really hoping to try & discover the origin of this fine gun. If anyone has any pointers to deciphering the random markings or any hints as to who Mr. Schüler is/was I would really appreciate it!

View images by opening the weblink in a new tabb, ie right click and open image in new tab. Images too large to display n the forums, NitroX edit:

https://i.imgur.com/PyuOh5c.jpg
https://i.imgur.com/yBGFnKg.jpg
https://i.imgur.com/96As5Ew.jpg
https://i.imgur.com/Y09QxGd.jpg
https://i.imgur.com/oJDqewV.jpg
https://i.imgur.com/s1ZwaHq.jpg
https://i.imgur.com/URy0TvL.jpg
https://i.imgur.com/55V68mP.jpg
https://i.imgur.com/i7fbojY.jpg
https://i.imgur.com/3af0D1K.jpg
https://i.imgur.com/hHVntGM.jpg
https://i.imgur.com/gE3mxkf.jpg