There are 2 sceneries: if you are shooting at a target(deer) with a subsonic rifle you will hear the impact after the shot.

If someome else is shooting and super sonic rifle and you are down range of the target(deer) then you will hear the impact of the bullet then the report of the rifle.
"Thump then boom" even though the boom happens first the bullet went supersonic and is faster than the sound of the report when it hits the target(deer) . Now the two sound waves are "in a race" and depending on the range the thump will get there before the boom. If the person is shooting the other direction ( away from you) then you wont hear the impact of the bullet. Clear as mud but I have "heard" this happen.