resizing, as it applies to the neck area of the brass, squeezes it down from its fired size. thats intentional - its how we get neck tension (grip) that keeps the seated bullet in the case at a consistent length and helps us achieve good consistent ignition. you dont want your bullets moving during chambering or while the gun is recoiling. this can do all kinds of bad things, including the possibility of over pressuring your newly loaded ammo if the bullet get set back too far into the case.
as to how tight the guide/pilot is (the stem part that goes into the case with the lyman system) by necessity should be relatively snug. thats how you get a nice true square trim. the sloppier it is, the more likely you are to have a trim thats not consistent, or even has burs/jagged parts because the cutter face will be flopping around. especially when spun at drill speeds vs doing it by hand.
if you want, try spraying some case lube on the pilot and see if that helps. however you should be making sure that when you're spraying your case lube onto the brass before sizing that you're getting it inside the necks too. lubing the inside of the neck is as important as lubing the body so that the sizing button on your die moves in/out easily and doenst over stretch the necks or damage the shoulder during resizing.
thats one of the reasons i like the plastic shoebox for applying One Shot (or spray lubing in general)... the cases tend to stand up and you get lube down inside the neck as well as on the outside by spraying from a slight angle.
hth
