Basically, this.My humble opinion, you would need to find the node for each bullet as different brands will be made differently. That would require tailoring all of the factors for the best accuracy.
A skilled reloader can develop a very accurate loading from any match bullet.
In order to distinguish the accuracy potential of Sierra SMK versus Lapua Scenar you would need to develop a load for each (120 rounds) and then shoot at least 100 rounds each to see which one was actually 0.05" better than the other. Were you to compare the entire line of Sierra versus Berger versus Hornady versus Lapua; your barrel would be worn out and you'd have to start all over again.
So, just pick one, then develop a loading that shoots really well, and call it a day.