Well Schmed what it sounds like is happening is that you are getting a little quick at the top of your swing. Try to slow down your tempo and accelerate through the ball not to the ball. A good drill for this is to take your 5 or 7 iron and try to hit them 100 yds using a slower body turn not just your arms. This is a good drill to help slow down your transition from back swing to down swing, it will also help improve your tempo