Thread: Neck Tension Issue... I think

+1 for definitely running a brush down the neck before re-sizing. How many firings has brass been through ? have you annealed the brass ? After 2 or three firings the brass will harden & neck tension will get variable.
Did you by any chance weigh the powder aft you pulled the pills ? Worth doing for a few just to confirm you did not some how end up with variation in powder loaded.