AT-1
crew in unit (625) was 3 not 4
and has two MGs not one
was produced in series 10
http://rkkaww2.armchairgeneral.com/w...htm#11.%20AT-1
first two example were build in spring 1935
What did you thing shold be in class prototype or meby as a serial produced vehicle?
About SU-37 and SU-45 prototypes they were based on T-38 chasis but that is important they never can swim like T-38
SU-3 used the same gun as SU-4 that was DRP Kurczewskij Recolies gun in game weapon 47