I heard the question 'what happens when an Unstoppable force hits an immoveable object?' and I thought that the force would just go through the object, is this possible?

If a bullet is fired directly at the Earth at a velocity X and an identical bullet is dropped - assume they are spherical and there is no rifling in the gun, just to keep things even; is there an altitude Y from which they would hit the ground at the same velocity? (I know they will not hit at the same time). Or perhaps a range of altitudes?