When Hungary separated from the Austro-Hungarian Empire after World War One, it began to slowly rebuild its military equipment. The eventually led to carbine conversions of old M95 rifles using the new 8x56mm rimmed cartridge, which were designated the 31M. However, the Hungarians were not satisfied with the Mannlicher straight-pull system. In cold conditions during the war, these rifles had sometimes become very difficult to operate, as the grease in their bolts solidified at low temperature. Hungary wanted to adopt a new turnabout rifle, and the 35M was eventually chosen. Building up to that, however, was the prototype 33M design.
The 33M was a rifle with a lot of fine machining and expensive, sometimes delicate, features. It used a sliding dust cover on the bolt that never would have survived field conditions. It also had a quite large oil bottle in the buttstock, accessed by pivoting the whole buttplate off to one side. Eventually the most egregious of the fancy bits would be removed, and the resulting 35M adopted by Hungarian forces (and later adapted to 8x57mm as the 43M for German troops).
Many thanks to Joschi Schuy for giving me access to film this extremely rare rifle!