I only neck size my cases until they start to chamber hard. Then I use a FL die, but I adjust it so that it only minimally resizes the case. I do this by turning the die down until it bumps the shell holder at full up stroke, then turn it back about 1/4 turn. This causes the die to just barely bump back the shoulder. I test the resized brass to see if it will chamber easily and then proceed to resize all the cases in the lot. I usually get about 4 or 5 firings out of my brass before this is necessary.

One note: If you're loading for a pump or semi-auto rifle, I's a good idea to FL resize the cases every time because these actions don't have the strong camming leverage that bolt actions have. Even a slightly snug fit can cause the rifle to fail to go into battery or extract.

Mike