I guess the first rifle came from Sveden to the USA too, as that peep sight is a design often found on prewar Svedish rifles. Certainly both were intended for elk = moose hunting. During the interwar years, there were several German rifles built on unusual, former “WW1 enemy” bolt actions. F.i., I have seen 3 such rifles built on type 30 “hook safety” Jap. Arisaka actions. And there are many Austrian hunting rifles on Italian Mannlicher-Carcano and Rumanian Mannlicher actions, sometimes combined with Mauser type bottom metal. Such actions came from unusable military rifles, surrendered or battlefield pickups from WW1. Such actions were probably even cheaper than stripped ex-military Mauser actions.
Here the actions come from an early American M 1903 Springfield, most likely battlefield pick-ups from early 1918. As the .30-06 cartridge was unknown and unavailable in Europe, only the action was salvaged and scrubbed off all original US markings.
The actions were rebarreled with a round, ribbed barrel and restocked, most likely by a small Zella – Mehlis shop. It was proofed by the Zella – Mehlis proofhouse 9.31 = September 1931, gun number 254 proofed that month. 24 and 25 are most likely the serial numbers of the gunsmith. The rifle with a bore/land diameter of 10.1 mm and proofed for a service load with a steel jacketed 22.5 g = 347 gr bullet, it is certainly in 10.75x68, the only such cartridge widely availble in 1931. What’s unusual here: The CROWN + crown/N proofmarks show, it was proofed using the pre-WW1 “4000 atm proof powder”. The use of these proofs usually ended in he early 1920s. Maybe the Z-M proofhouse still had some leftover 10.75x68 proof cartridges in 1931?