It also saw combat in the Winter War against the Mannerheim Line fortifications .
The first combat use of the ML - 20 was in the Battle of Khalkhin Gol , in limited numbers .
ML - 20 also saw combat in the Winter War against the Mannerheim Line fortifications .
The first combat use of the ML - 20 was in the Battle of Khalkhin Gol , in limited numbers .