I was going to stay out of this for fear of being flogged, BUT. Personally I use 7.5's for grouse and I would agree 10's sure sound small to me. Recently I picked up an older 16 that needs 2.5" diet and I think I am going to try Roy's idea of going to 6's.
That said, Burton Spiller swore by #9's for grouse. This was a man that would go back to his home to get one of his dogs, if the dog he was hunting over could not find a downed or wounded bird. He once went out the next day to find a wounded bird, because it so haunted him, and found it I might add.
There had to be something to the smaller shot size in times gone by. I don't know anything about Hammond, but anyone would be hard pressed to suggest Burton Spiller was not a humane grouse hunter.
