RE: Lee
Try loading the brass in the chamber before resizing them and see if they are already tight. I have seen brass from hot loads that are a bit snug just from firing. Could be the chamber isn't perfectly round and it did not go back in the same as it came out or something like that. Neck sizing with the Lee colletshould not change the case from loose to tight unless there is a problem with the length of the collet or insert. Check them before and after sizing and see if there is a difference. Take the firing pin out to feel the case only when test fitting will help in the feel department. Good luck.