His initial was added to his gun 's designation in recognition of his contribution : the ZiS - S - 53 .
Savin was put to work modifying Grabin 's gun to fit the new turret and incorporate other improvements .
Grabin 's initial was added to his gun 's designation in recognition of his contribution : the ZiS - S - 53 .
Savin was put to work modifying Grabin 's gun to fit the new turret and incorporate other improvements .