Kevin,

The feedback we have been getting for 712 AP's has been phenomenal.   I have heard anyone having a hook issue just because of the new head.  If your clubs are a little more upright than your previous set, it could cause you to hit some hooks.  Have you checked the lie angles on the new clubs to make sure that they match your 710 AP2's?  I would start there.  The narrower sole reduces drag for better turf interaction and should keep the heel from catching as much also.

I you have matched all of your 712 irons to your 710 specs and your still missing left, than I would go see your PGA Professional for a tune-up.

 

KL

Did you change your shafts also? Last year, I switched to a little bit heavier shafts which, not realizing, slightly change my grip. I was holding the club a little bit underneath and strong with my right hand which caused my misses to hook. Hope this can be some help.