There's no way I'm buying the story of an 80 grain powder charge behind a ball OF ANY DIAMETER bouncing off a deer at 40 yards and only leaving a bruise UNLESS the deer was length-wise to the shooter WHEN THE BALL STRUCK, not when the hammer fell. ( they are not the same thing ).
If the deer was lengthwise to the shooter when the ball struck, the ball could have passed close alongside the deer's body, possibly glancing off a bulge of skin and muscle as it zipped by.
Sometimes deer can change their orientation to the shooter unbelievably fast when startled. This one may have been broadside when the shooter pulled the trigger, then whirled, or jumped about the time the shooter yanked the trigger.
Maybe the shooter shut his eyes and flinched while firing, and the deer's movement was not seen.