Ok just a few more but this is good info from this thread,
(watch now, Murphy will probably pop in on us and say, "aww changed my mind on that a few yrs back,..." )
another from Murphy
A little more neckin'....
You could go down a little bit more maybe leave about .025-.030" unsized neck. This will be a fraction of a turn with the 7/8" x14 die threads. The purpose of neck sizing is to prevent setting the shoulder back. Some f/l sizing dies, or specifically some fired brass, due to chamber dims, can't set the shoulder back anyway. This is due to minimum headspace dimension of the chamber. Dies are made to reestablish that minimum headspace dimension when screwed down to contact the shell holder. If the chamber is already cut to the minimum, then the die wont move the shoulder. That's a good thing. You would notice this if you tried to fit brass fired in another rifle, into your chamber. It wouldn't go.
You're doing it correctly. Size a little at a time and look for the mark of sizing on the neck. You could do quite well with where you have it now, but I would go a little closer to the shoulder. Wherever you end up sizing, lock the die down and use that setting each time to avoid variations in neck tension. This is a minor factor in accuracy. We want consistent neck tension from shot to shot. A neck only sizing die is available for about $20.
Make the shot,
this is RayfromAk
It's much easier and accurate just to use a neck sizing die. Both the neck and full-size die can be adjusted as follows, but first have fired once or fired twice cases from the same batch:
1. Dip the case's neck in powdered graphite, and then size the neck with the neck sizer, or the case with the full-size die.
2. Look at the neck carefully, and see how far down on the neck toward the shoulder a ring of graphite has moved to. Adjust the die (a little at a time) so that in the following sessions the line or ring moves to where the shoulder and neck meet, not above, nor on the shoulder, but exactly between the two.
3. Dip the same case's neck in the graphite, size the neck (or case), watch the ring of graphite, and adjust the die as needed. Continue doing this until the ring has moved just between the shoulder and the neck.
4. Once the ring has moved to the correct place, grab another fired once, or twice, case and size that one in the same manner as before. If the ring of graphite still is in the same location as before, then back the the die 1/16th of a turn, and lock it in place.
To lock the die in place:
1. Place a deep-well mechanic's socket on the shell holder. In can be placed right on top of it, but use the right-size socket so that it does not go inside the die and damage it (find the right size socket).
2. Move the ram so that the socket is firmly pressed between the die and the shell holder, and perfectly centered, and hold it that way until you lock the die in place.
Don't forget to also lubricate the case up to just below the shoulder if you are using a full-size die.