Thanks for the information. Although silly to carry a gun with this kind of grip safety in the field for the reason given by Joe Wood, the mechanism could have been useful in a duck blind. You could lean the gun against the wall of the blind at full cock waiting for the ducks to decoy. Picking it up to swing and in the process gripping the wrist and releasing the safety would be natural in that setting. I say this because I have seen this grip safety on an 8 1/2 lb. John Manton duck gun (a flintlock conversion) with shackles for a strap to carry the gun likely back and forth to a blind.
