Not all out of round bullet holes
are keyholes. Note the hole to the right. Looks like
the bullet went through the target sideways. But it
didn't. The target was printed on cheap 20 pound
copy paper and the paper tore as the bullet passed
through. The torn part of the paper is folded back
away from the front of the target.
When this happens, there will be a
flap of paper attached to one side of the hole at
the back of the target. A dead-giveaway that this is
what happened is the perfectly straight end of the
hole where the paper is folded. This fold will
almost always be perfectly straight.