You will find that revolvers, especially with longer barrels, are more sensitive to grip impacting the difference between POA/POI and causing inconsistent POI. In a semi-auto it doesn't make a difference because the slide and barrel assembly are only connected to the frame via the recoil spring and frame rails when the bullet is still in the barrel. The bullet is long gone by the time the frame receives enough energy to start torquing.
Check out these great videos
Tripp Research, INC. Hi-Speed Video
