On Monday I played another round at my local course. Ended up with a good score in cold windy conditions. I attribute my scoring to solid iron play.
I was hitting my irons particularly solid that day and I think a lot of that had to do with a light grip on the club.
With a light grip the club seemed to swing more freely and with less effort. On a day when my shots should have been 1 club or more shorter than in the summer, I was getting my full distance and then some. With a light grip I could really feel the acceleration of the club down through the impact zone. I could really feel the ball compress and even though I was playing a non-tour ball (Nike One Vapor), I was still getting a lot of spin, much more than I anticipated.
The other interesting effect that the light grip had was on the flight path of the golf ball. I had a number of shots during the round when I know I had a tighter grip on the club. On those shots, I tended to lose the ball to the right with a weak fade. My shots with the lighter grip were controlled draws.
So there were several benefits from using a light grip:
1) More solid contact
2) More clubhead speed
3) Controlled draw vs a weak fade
4) Optimal spin
5) Improved Distance and accuracy