Pedzisa mutsara unotevera: M21 yakashanda kuWestern Front, ichiona chiito muNormandy uye mu
kumaodzanyemba kweFrance, isati yashandiswa gare gare mukati meHondo yeBulge, Hondo yeBelgium, Operation Market Garden, uye kupinda kweGermany kubva kumadokero. M21 yakashanda neUS 3rd, 1st, uye 7th Mauto panguva yemushandirapamwe muFrance, uye 2nd Armored Division, iyo yakaigadzira. Mukuwedzera, mienzaniso 57 yakabhadharwa kumauto eFree French. Pakazosvika 1945, chakaziviswa kuva chisina basa, nemhaka yesimba risina kukwana remarata ye81 mm sechombo chemapurisa.