The Stechkin automatic pistol or APS (Avtomaticheskiy Pistolet Stechkina, Russian: Автоматический Пистолет Стечкина) is a Soviet selective fire machine pistol. It bears the name of its developer, Igor Stechkin.
This video is in Japanese. The Stechkin shoots 9mm ammo and according to Wikipedia the rate of fire is 750rds/min. It sounds faster than that to me. As you can see in the video, the Stechkin has a wooden stock similar to the Mauser C96 stock.