Rudolf Frommer was a self-taught engineer and firearms designer who worked his way up through the FEG concern in Budapest to eventually hold the position of CEO. During this time he developed a series of long-recoil, rotating-bolt pistols culminating in the Frommer Stop, which was adopted by the Austro-Hungarian military. At some point during this time he also produced this prototype rifle, which is similarly a long-recoil rotating bolt design. I have no information on its production or performance, but I will give you as much of a look into its operation as I can.