Love the effect of the spell -- very cool -- as well as the close-up of Harry's eyes. My thinking is just that Harry's magic/energy was drained as a result of firing off the AK, versus a deflection. Or at least that's what it looks like to me. *gives you the look just for good measure*
*grins*
This piece is epic and beautiful, and although I have not seen the final piece(s), I'm already so thrilled that you went for it. You should be so very proud of yourself for this accomplishment.