▁Commonwealth ▁units , ▁Soviet ▁Red ▁Army ▁personnel ▁t ended ▁to ▁refer ▁to ▁the ▁M 3 ▁as ▁the ▁" Gr ant ", ▁even ▁though ▁all ▁of ▁the ▁M 3 s ▁sh ipped ▁to ▁Russia ▁were ▁techn ically ▁of ▁the ▁" Le e " ▁variants . ▁The ▁official ▁Soviet ▁design ation ▁for ▁it ▁was ▁the ▁М 3 ▁сред ний ▁( М 3 с ), ▁or ▁" M 3 ▁Med ium ", ▁to ▁distinguish ▁the ▁Lee / Gr ant ▁from ▁the ▁US - built ▁M 3 ▁Stuart ▁light ▁tank , ▁which ▁was ▁also ▁acquired ▁by ▁the ▁USS R ▁under ▁L end - Le ase ▁and ▁was ▁officially ▁known ▁there ▁as ▁the ▁М 3 ▁ лё г кий ▁( М 3 л ), ▁or ▁" M 3 ▁Light ". ▁Due ▁to ▁the ▁vehicle ' s ▁pet rol - f uel led ▁engine , ▁a ▁high ▁t endency ▁to ▁catch ▁fire ▁and ▁its ▁vulner ability ▁against ▁most ▁types ▁of ▁German ▁arm our ▁the ▁Soviet ▁troops ▁encountered ▁from ▁ 1 9 4 2 ▁on wards , ▁the ▁tank ▁was ▁almost ▁entirely ▁un pop ular ▁with ▁the ▁Red ▁Army ▁since ▁its ▁induction ▁into ▁the ▁Eastern ▁Front . ▁ ▁With ▁almost ▁ 1 , 5 0 0 ▁of ▁their ▁own ▁T - 3 4 ▁t anks ▁being ▁built ▁every ▁month , ▁Soviet ▁use ▁of ▁the ▁M 3 ▁medium ▁tank ▁decl ined ▁soon ▁after ▁mid - 1 9 4 3 . ▁Soviet ▁troops ▁still ▁field ed ▁their ▁Lee / Gr ant ▁t anks ▁on ▁secondary ▁and ▁qui eter / less - action