Reloads are generally the best because they are tailored to a specific rifle, Factory loads you would be looking for ammunition labeled "match" but even then different brands will shoot better or worse you need to try out different ones to find the one your rifle likes to eat because different grain bullets different powders different primers will all give a different result.
For factory ammo buy a box of a few different brands of match grade ammo and give them a try its really the only way to find which one your rifle will like to eat the best, Or get into reloading and go that route. I would say more champion shooters use reloaded ammo over factory