Every rifle is different and will "like" some loads more so than others. The only way to discover which factory load is most accurate in your rifle is to purchase as wide a range of ammo as you can find in bullet styles and weights that are appropriate for the game you intend to hunt. i.e., purchase ammo intended for big game, not varmints, if you're going after deer, elk, moose hunting, etc...
Shoot 5 round groups from a steady rest, sandbag, etc...allowing sufficeint time between shots to allow the barrel to cool and prevent vertical stringing. Shoot all the ammo and make sure you carefully label each target with the type/bullet weight of ammo you used.
It might take you a couple of trips to the range to do this properly. Once you have all your targets in hand, break out the calipers and measure to see which ammo shot the smallest groups. If I have lots of ammo, I usually pick the top two or three and shoot several additional strings just to make sure the original results weren't the result of random chance or unknown variables. The most accurate group out of that, will yield the factory ammo your rifle shoots best....I'd then go lay in a good supply of this ammo, making sure that the factory lot numbers match. Kept in a cool, dry place, factory ammo can last for years with no degredation in performance.