Concentricity helps to ensure proper bullet seating in both the case and the chamber of your firearm. Higher concentricity also aids in a uniform release of the bullet on firing for optimal velocity and accuracy. Benchrest shooters have long known that uniform case wall thickness is vital to accuracy. Hornady unprimed brass rifle cartridge cases are manufactured to extremely tight tolerances to ensure this critical element is as consistent as possible. They treat Hornady brass as the foundation for an accurate cartridge not a commodity. Because Hornady takes greater care in its creation you'll get more reloads from Hornady brass. Every single Hornady case regardless of the lot in which it was produced is virtually identical to other Hornady cases in the same caliber. For you this means consistent pressures velocity and accuracy - every time.