At what time in the life of the bore? :lol: All of mine have changed over the last several hundred rounds. Overall, the best at this time is the federal Vmax, but the 20gr XTP shoots real good too, just to a different poi. Different lot numbers of the same ammo will shoot different too, so it would behoove you to buy more of the best shooting stuff if you can get the same lot. My 917VS also likes the hornady Vmax, FWIW and some of the Remington, but not every lot number I've tried!