l tried to answer this very question a couple years ago..
l took my 629DX, 629PowerPort,629PC Magnum Hunter, 629PC Light Hunter, 29 P&R all to the range one day...Shot 2 each 5 shot groups with the SAME ammo with a KNOWN accuracy load. 7gr Unique, 240gr swaged Speer SWC.... Guess what. The DX didn't win, Neither of the PCs won,
lt was a kinda tie between the 29 and PowerPort....