Size using expander ball?You want to FL Size, trim to common length, then expand on an expanding mandrel meant for getting ID to turning diameter, then turn necks.
At this point, you may need to size again to get neck tension right.
After sizing and trimming, I would look at neck thickness variation. Standard Peterson variation might be better than you can turn to accurately!
I do, but I may slightly overwork necks. The point is to get the case shape right before trimming for length. I fl size.Size using expander ball?
If I don’t trim accurately, it is impossible to set up the stops consistently on my k&m tool. This is critical to just barely cut into the shoulder. Other tools may be different.The only sizing prior to neck turning should be with the turning system expander mandrel -on new/unfired brass.
How did you control trim length?I recently turned several hundred pieces of Peterson brass. The base to datum was exact on each case, a rarity, so I just ran the turning mandrel without sizing.
Normally I would FL resize without the expander ball, then expand with mandrel in necks lubed with Imperial Wax.