You are not going to engage a IFV with 100mm HE at 4000 meters, anti tank projectile yes, HE or 30mm no way.When we speak about IFV to IFV engagemant, so why not use 100mm MG if it does work against any western IFV (exept Israeli Akhzarit however) even with its HE? In addition I must note that the maximum range of aimed fire of its 100-mm gun-launcher with projectiles - is also 4000 m (you can found its number on its official site http://www.kurganmash.ru/en/machines/bmp3/serial_bmp3/ ) You will naturally enjoy when see at the video how good its gun works on daylight as at night: http://www.kurganmash.ru/en/machines/bmp3u/fire_power/vesna-k/