I have reloaded several hundred .223 rounds with no issues at all. My .375 H&H is another story. With both speer hot core and 300 gr. partitions i am having maybe 1 out of five rounds that are pressing of center. When i called tech support they suggested it was the case necks not being a uniform thickness. Well i am a machinest by trade and know how to measure things. I checked a few of the hornady cases yesterday. If there is a wall thickness variation its less than half a thousandth. Any suggestions or thoughts.