One problem with larger tank guns, and the very high speed APFSDS shells, is the long distance the smaller "penetrators" can travel, and the "safety area" required to prevent off target shells from hitting someone. Although the shell is 120mm, the actual penetrator is much smaller (to get the higher speed). NATO 120mm APFSDS requires a range with at least 130 kilometers of unpopulated space downrange. Russian made 125mm APFSDS shells require at least 80 kilometers.