This rifle, as best I can tell, is a prototype model made by Steyr in Switzerland in the early 1930s for use in Hungarian military trials. The Hungarians were looking to replace their old 1895 straight-pull Mannlicher rifles with something more modern. They wanted to keep their Mannlicher en bloc clips and ammunition, though - note the same distinctive magazine on this rifle and the M95.

The action that Steyr used for this trials rifle came from an effort to produce an improved German rifle during World War One. The Gewehr 98 had a number of serious deficiencies in trench combat, and Mauser developed an improved model in 1917. It was intended to enter production in 1918, but the collapse of the German armies prevented that from happening. The 98/17 had a flat tangent leaf rear sight, a sliding dust cover, and detachable box magazines, as well as being shorter than the G98. While it was never made in Germany, it did form the basis for the Type 13 Mauser that was manufactured in Manchuria with Steyr's assistance. So when the Hungarians put out a request for rifle models, Steyr dusted off this action, fitted a Mannlicher type of magazine, and submitted it (note that the dust cover is missing from this rifle, although its mounting grooves are still there).

Ultimately, this did not win the competition, and Hungary chose a Mannlicher action rifle as the 35M instead.