For FL sizing dies that have an expander ball I lube inside necks. I use an appropriate size bore mop with lube applied to mop. Since I'm an old fud I still use RCBS lube. You could apply your One Shot to bore mop.
When inserting mop into case neck I try to ensure I get a good dose of lube at inside shoulder/case neck junction. This is where expander ball engages neck first, so most important imo.
Some brass will develop a doughnut for lack of a better description at the shoulder/neck junction due to brass flowing here during the case firing. This brass flow is why cases need to be trimmed as needed due to aol increases.
Your cases may not have this doughnut. Probably not, dunno. However, doughnuts do add additional resistance when retracting, pulling expander ball out of case potentially moving shoulder/neck junction to where case seems to have headspace changed. Result might be the shiny ring displayed as on case in your photo.
If you have a fired case that bolt closes ok on, remove the expander ball from your FL die and size case. Then see if sized case <that expander ball has not been pulled through neck> chambers and bolt closes ok.
Please post results if you do this.
Did it this morning. Took an unsized RP piece of brass, it chambered fine. Ran it through the sizing die ( with the shell holder adjusted to just cam over a tiny bit) and chambered again. Again it chambered with no resistance.
