Initially losing to Simonov’s AVS36, Tokarev’s design was later retried and adopted as the SVT 38, later becoming the SVT 40 after the Finnish Winter War debacle that the Soviet Union found itself in, just prior to the Second World War.
Very forward thinking in many aspects of the design, the rifle featured a 10 round detachable magazine, short stroke gas piston operated tilt locking bolt, and an extremely lightweight construction compared to numerous other designs of the time.
It was also the second most produced semi-automatic rifle of the Second World War after the M1 Garand, with over 1.6 million rifles manufactured during the war. Had it not been for the war itself, the SVT 40 was well on the path to completely replacing the Mosin Nagant.
But with the changing infantry tactics against the German Army, and the severe shortage of manufacturing capability, in addition to some reliability and accuracy issues, led to the diminishing usage of the rifle during the war, with product ceased at the end. Of course, Simonov got the last laugh with elements of his AVS-36 being incorporated into the 7.62x39mm SKS, making the SVT 40 obsolete by the war’s end.
Sources: TFB Youtube, Miles V