The American magazine National Interest spoke about unusual Soviet experimental models of machine guns that were never taken into service. 

The list includes TKB-011 & TKB-022, AK-47, TKB-0146, and TKB-59

According to the source, the KTB-022 and TKB-011 family of prototype bullpup rifles “look like something out of an alien/predator movie.”

“TKB-0146 was one weird rifle. Despite its odd outward appearance, what was stranger was its rate of fire. Its safety selector has three firing positions, single, automatic, and burst, plus safe,” the source noted. “Three barrels, all black, and a bullpup— the TKB-59 was an experimental design that attempted to increase hit probability. The idea was that with multiple projectiles, a shotgun-like effect could be achieved, theoretically increasing the percentage of shots on target.”

According to the authors, despite the fact that the above samples were never taken into service, they became a platform for experiments and helped Soviet gunsmiths expand their capabilities.