Unique Unidentified Prototype 22 Pistol

A simple model and renders of a bizarre one of a kind pistol that according to the auction house that sold it claims that its supposed to be an American prototype semi automatic pistol chambered in "22" not that helpful as there are loads of "22"s out there and what made modeling this a challenge was that there were only 2 side profile pictures of the piece no front pics at all so I could not have know how thick the thing would have been. Also there were no pics nor explanations of its internals so I had no idea on how the thing operated or worked so I had to guess that the things bolt operated similarly to the bolt of a Winchester 1887 and its magazine would have been similar to the Spencer carabine. The pistol most likely was a work shop prototype as the pistol has never had a Finnish and certain small detail look to have been made with hand operated tools.

The page where I found it - https://www.icollector.com/Unique-Unidentified-Prototype-Pistol_i10495034