To meet the OP's criteria each and ever shot has to be within plus or minus 1/8" of the absolute dead center for both POI and group size. Even at 25 yards with the best ammo and equipment (which I have) I don't believe I would claim I can do it consistently.
On the other hand I am more than willing to take a bet for anyone that claims they can. Any takers for say $100 per group for 5 groups at 50 yards? Even at 25 yard that's going to be a safe bet except for a few world class shooters with world class equipment.