I have to admit I didn't follow this thread because I've never had the problem I ran accross this in Robert Churchills book "Game Shooting"

Quote:
"Most people think that they grip a gun naturally and correctly. All too often they do not. The tendancy is to carry the right hand far too much round the top of the stock. This checks it coming up and forces the knuckle of the second finger hard against the rear of the trigger gaurd (another cause of bruised finger)."

Another cause he listed.
"If you grip too tightly while mounting the gun to the shoulder you may relax on the instant of firing. Bruised cheek or finger is sometimes and indication of too light a right hand grip at the instant of firing, though more usually it is due to the error in stance indicated in the previous section"

Another cause...
"In my oppinion the grip of every normal gun should be tapered from the direction of the breech; that is to say it should be thicker in front of the hand than at the rear, thus offer a cone to prevent the hand from slipping forward under recoil.
Very often one sees a grip tapered the reverse way. Such guns tend to slip through the fingers on recoil with bruised second finger for result"

jOe