If you are chunking you are most likely coming down on the ball from a steep angle.  Try sweeping the ball more.  Are you trying to swing extra hard?  I notice I chunk it if I'm trying to hit it hard.  When I relax and just let the club do the work the result is much better.

I got this from Loreana Ochoa in Golf Digest...............drag your FW's back low and slow so you can"hear" the grass;  do not have a too steep take away...........then try to also follow through low to the ground for about 12 to 14 inches and then follow through with your normal swing follow through(try and not pick the ball up...enough loft on the club)  I only carry a #4 wood and am playing it about 2-3 inches inside front heal.  This tip has really improved my fairway woods.  Just try to sweep instead of "pinching"

                                                                                                                                                                 Coachwags