Some things I have learned by "experience". I define "Experience" as "Mistakes which I have survived".
There are dies that are called Full Length sizer dies that do just that; depending on the way the die is adjusted. At one time, instructions which came with these dies said to set the die in the press so that the bottom of the die was in firm contact with the shell holder when the press ram was raised. What the instructions didn't say was that if this setting produced the correct amount of sizing, you were very lucky.
These dies may be adjusted to size the case too much or too little; that is the die may be adjusted to not even touch the shoulder or to push the shoulder back too far. During this process, the sizing action upon the body of the case will vary. If the FL die is adjusted to push the shoulder back, the body of the case will be made slightly smaller and vice versa. I have one FL size die that was several thousandths of an inch too long to properly size cases. I ground a little off the bottom of the die to let it go lower in the press--could have taken a little off the top of the shell holder, also.
As with most things, there is a "sweet spot". If loading for a bolt action, I like to adjust the FL size die to produce a slight resistance when the DISASSEMBLED bolt is closed on the sized case. To do this, I put the size die in the press with about 1/8 inch space between the bottom of the die and top of the shellholder. I then size one case and observe how far down the neck it is sized. I screw the die a little farther into the press, and size the same case again, checking the neck to see how much of it is sized. This process continues until the sizing action approaches 1/32 inch or so from the shoulder.
I then try the case (after removing the lube) in the chamber. Usually the bolt won't close. Continue the process, turning the die deeper into the press very slightly until the disassenbled bolt will close with very slight resistance.
This die position produces, for me, the fit and feel which I like and which I have found to give trouble free functioning and fine accuracy FOR MOST PURPOSES. Be aware that this technique can get you in trouble if you get any debris (grass seed, pocket fuzz, leaf fragment etc.) in the chamber. For really important shots (dangerous game, self defense and so on) I would want the disassembled bolt to close of its own weight.
I don't use Neck Size dies--I don't do Benchrest. No slam on BR shooting, we owe those guys most of what we have as far as accuracy is concerned.
With that said, Neck Size dies, as far as I know, don't size the case body. I don't think BR shooters (except the 1K guys) stress their cases nearly as much as we do. They can wear out a bbl. with relatively few cases; we usually do very well to get 10 reloads from each piece of brass.
Most BR loading techniques are very adaptable to our use, however, to try to use BR sizing techniques for full steam hunting loads can cause some problems.
When I load for semi-auto rifles (seldom, but I do have a couple of Garands) I use a case gauge to determine proper sizing. Yes, the cases are overworked, but they get very battered in the action anyway. Usually only last 3 or 4 loads.
My $0.02. Flame suit on!
Jim
