The trigger finger freeze is a form of flinching. In fact, it is usually accompanied by the whole body lurching after the initial freeze. A couple of possible solutions:
First, if shooting sporting clays (or obviously wild birds) use a low gun with the butt quiet low, below the chest. Put the end of the barrel where you expect to first be able to focus on the bird. When the gun is properly mounted it will be tracking the bird with the bead. When the gun hits the shoulder it should be where it belongs and the shooter can fire immediately. Don't track the bird too long. Trying to follow the bird or be too precise can cause the freeze. (And its a bad way to shoot anyway.)
Another thing that often helps is to start with the trigger finger well off the trigger. When it is time to shoot "slap" the trigger. Don't start with the finger tense and on the trigger. It should almost be pushing forward.
In fact, I had a very good friend (God rest him) who was a AA 27 AA trapshooter and also superb on skeet and sporting. He cut out an ordinary rubber eraser and made it fit the inside front of the trigger guard. There was some distance in front of the trigger to this eraser. More than enough for the finger to have some room. My recollection was it was at least two fingers from the trigger to the eraser. The eraser was shaped with a groove in a semi-circle toward the front of the gun. He glued it into the front of the trigger guard. He would literally push his finger forward against the eraser when calling for the bird. Then slap when firing. It was almost like a reverse release trigger. It worked very well for him and eliminated most tendency he had to flinch.
Good luck to your friend. Let us know what happens.
Oh, P.S.
Flinches of this type are sometimes caused by a stock that is too short. That should be checked.
Regards, Jake
