Re: Bullet lube when seating?
I used to use graphite suspended in alcohol but that was prior to sending all of my dies back to the manufacturer and having them hone the necks to 0.003 smaller than a loaded brass. No more use for expander ball/button and no need to lube.
When you hear that horrible squeak and feel the roughness when that button is expanding that neck back to spec, that tells me your die is downsizing your case neck a lot and probably way too much.
Take that button out, size a case and take a caliper to that neck after squeezing without the button. If it's more than a few thousandths difference, the die is overworking the brass. My Redding 270 die was squeezing my necks down about 15 thousandths more than a loaded round. Think about that. A fired cases was several thousandths larger than a loaded round. That's way too much work on the case and a lot of potential runout.