The AKB-15 was a project developed by Arex Defense in Slovenia in 2015. The company received a request from a small country (they decline to reveal exactly who) to modernize a stock of AKM rifles with adjustable stocks, pica tinny optics mounting, and new barrels among other features. Arex developed a monolithic aluminum upper assembly (the production model would have been made from an extrusion) and put together 100 examples for military consideration.
At the same time, they planned to release a semiauto version of the same thing on the civilian market for collectors and sport shooters. The civilian model would have been built on the tooling financed by the military contract. So when the potential client country decided not to adopt the rifle, the civilian version was left in the lurch, and will almost certainly never see production. Only 15 semiauto examples were made, and they have all since been sold off within Slovenia.
Thanks to Arex for giving me access to this example (the former factory owner’s personal one!) to show to you.