Question:   

In preparation for this season, this past weekend,  I decided to start shooting my bow.  Four of five shots were slamming my left wrist ????? Could the length of my arrows be my cause?  Any tips would be greatly appreciate it... I know my wrist will ...Thanks For The Help.

Answer: 

No, it is not likely the length of your arrow that is causing the problem, it is probably your form.

As you hold your bow your wrist should extend in the same direction as the rest of your arm and be rigid.  If you allow your wrist to flex outward from that line, it deflects your arm into the path of the string.  As you draw your bow, look carefully at where your wrist is in relationship to where the string will pass as you release it.  People often think they need to nest the bow handle deep within their hand.  That often forces the arm into the path of the string - and that hurts!

I almost always use an armguard when I shoot.  I almost never hit it, but it only takes a couple of string slaps to start creating bad habits.

On other consideration is the bow itself.  This is less common, but possible.  Your bow may not be a good fit for you.  Every bow model is slightly different and it may be that the one you are using is just not quite fitted well to you. 

I would recommend to seek out an archery professional about your form and possibly your bow.  

Good luck.