I have found that I do not get alot of case expansion in my 308 and 223 cases. Therefore I always align my cases in the chamber, and fireform the brass. I let the chamber determine the neck alignment. I do not use a neck sizer, I use the Sinclair expander body. I believe if you are not neck turning then your main concern should be inside neck diameter-for the obvious reason of neck tension. I do not concern myself with centering the neck to the case after fire forming, however I do align my cases in the rifle chamber. The expander body will not adjust the neck to the case, it will only size the inside diameter of the case-which is what I want it to do.

I believe neck tension is crucial to accuracy, and I do not trust the standard expander ball to give me consistent ID. And I believe the neck die with the expander ball works the necks too much. If your necks are too large you can always bump them down by taking the expander out of the die before sizing.

The majority of chambers in today's rifles are oversized, IMO. I do not do alot of work to control the outside of the brass. I concern myself with the inside volume of the case, and neck tension. A main component to pressure is volume, so I try to control inside case volume as much as possible-hence the fire forming. I always trim. Tom.