While in tank (panzer or T-34 for example)
Switch rounds from AP (armor piercing) to HE (high Explosive). AP rounds just goes through on M3s/M16s and doesnt explode on contact (remember, they are not tanks loaded with volatile rounds inside the casings of the turret). HE rounds explodes on contact and i'm 1000% sure it will kill M3/M16 in a single blast.