I neck size until chambering tells me it is time to push back the shoulder a bit. I like a bit of resistance on bolt lock-up. I can't say it makes any discernable difference to accuracy but it does to case life. This especially true for my 35 Remington cases which will split at the neck after only a few firings if I FL size them. FL sizing makes my 308 cases in my 99f harder to extract. This is related to a tight chamber but generous headspace. Cases stretch backward and repeated firing and FL sizing leads to thinning at the head and the telltale "ring" warning of potential head seperation. I barely kiss the shoulder on these cases and I have increased the case life and my peace of mind. It makes sense that looser fitting FL sized cases would somewhat compensate for bore and chamber alignment issues. A tight fitting case may result in the bullet entering the lead on a slight angle or striking it off centre. Neither would be good for acurracy. I wonder if checking case concentricy before and after firing might not help diagnose this condition?