I am getting components ready to start reloading for 300 win mag. I just got some RWS brass in and started measuring a few cases. I found that the neck wall thickness varies from about .012 to about .0145 on each piece of brass that I have measured (a few had a little bit less variation). Is it normal for brass to vary that much in neck thickness? If I turn them down to .012 will that make them too thin? Im still kinda new to reloading, so yalls input is appreciated