In the book Hatchet by Gary Paulsen, how does Brian's first bow nearly spell disaster for him?

Like so much of what Brian endures, there seems to be an ongoing dialectic where he experiences something bad, following by something good, succeeded by something bad.  The bow incident is no exception to this.  His experience with the first bow spells near disaster for him, as it almost ends up wounding him.  I would pay attention to Paulsen's description of this event in the middle of the book.  Brian is able to understand how the bow was calibrated incorrectly and nearly hit him.  He grasps this, makes the modification, and then is able to produce a bow that is able to hit the fool birds and generate both a new source of food production as well as protection device.