If its been asked disregard, but was the brass you've got fired in your current chamber? If yes and you've got a decent amount, might as well use it. If not definitely start over.
I contend good brass makes a difference in many respects (accuracy & longevity). Not here to argue though. Peterson is cheaper than Nosler and will last 2-3 times longer. The "F" class guys swear by it. I did a comparison between the Nosler and the Peterson. I am not going to repost it but here is the link below if you want to see the results. Different brass does yield different results when hand loading. Case capacity, concentricity, flash hole & primer pocket uniformity as well a case life all come into play regarding brass. The big players are Lapua, ADG, Peterson and a few others.
If you build a nice rifle, why skimp on your brass.