Neck turning - need help on process

Discussion in 'Reloading' started by tlk, Sep 4, 2009.

  1. tlk

    tlk Well-Known Member

    Apr 11, 2008
    I tried turning some necks last night and has some issues. This was once fied brass, resized with a Lee Collet die. but the case mouth didnt fit all that well - there was enough slop to cause it to cut at an angle. This is confusing since a bullter wont slide in. I am using a Forster cutter for a .308 caliber, and the guide is correct (checked).

    What is the specific process you are using (how do you do it so that there is no slop), and when in the life of the case are you doing it? What am I doing wrong here?

    Thanks for your help.
  2. J E Custom

    J E Custom Well-Known Member

    Jul 29, 2004
    There are many ways to turn the necks and this is just the way I do it.

    First I full length size (New) brass ,Then I trim and deburr it.

    If the pilot doesn't fit snug I turn down a larger pilot until it fits well. You
    can also adjust the collet dies or the expander ball in the die.

    Then turn only until the neck cleans up all around ,no more.

    This way when the brass is fired the first time it is true and concentric.

    Make sure the cutter has a rounded edge on the side that cuts up to the
    shoulder of the case to prevent case neck separation.

    To do a good job the pilot must fit good.


  3. KDB

    KDB Well-Known Member

    Jun 26, 2009
    Everything I have read suggests that you really don't want to turn used brass. However, I have done it when brass was hard to find and this is the process I used:

    Cleaned the 1x fired case

    Neck sized it down to .002 smaller than my expander (Redding S-type bushing)

    Used Sinclair expander die to open it back up

    Used Sinclair neck turner set to clean about 90% of the neck (my guns are not tight necked so wall thickness is not a concern). Out of 100 cases, I will sample about 10 and measure the necks and take the smallest measurement to set my cutter depth

    Trim if needed

    Anneal the case

    Then standard reloading practice. Not as anal as benchrest guys, but close...
  4. KDB

    KDB Well-Known Member

    Jun 26, 2009
    Have you measured the case mouth after sizing and compared it to your pilot? Does Lee make different mandrels and collets for their dies in standard calibers? If so, then change the collet/mandrel to make up the difference for the pilot. Hope this helps.
  5. Mikecr

    Mikecr Well-Known Member

    Aug 10, 2003
    I turn only new(unfired) brass using Sinclair expander and turning mandrels.
    New brass is always undersize at the necks, so only expansion is needed.
    It's important to turn brass before firing so that you can cut some of the shoulder -turning into neck on firing(doughnuts). It's also important that expansion is the last sizing direction so that all thickness variance is outward for the cut.

    It's easier if you don't mix components in your process.
  6. woods

    woods Well-Known Member

    Jun 4, 2006
    Hey tlk

    I do it just the way you said you did except I turn new cases. IOW, run a Lee Collet Neck Sizer into the new case to size it to the Collet mandrel and turn. I get a tight fit.

    The only thing I can think of is that a once fired case has a little more springback. When the case is pressed against the Lee Collet mandrel it will springback in an outwards direction. With once fired cases the neck will springback a little more than with new cases.

    You could anneal and hopefully that would restore the new case elasticity to the necks. You could order a smaller mandrell from Lee. You could reduce the diameter of your Lee Collet mandrel by spinning against some sandpaper.

    Pics would help.
  7. MontanaRifleman

    MontanaRifleman Well-Known Member

    May 21, 2008
    Hmmmm... I have turned previously fire case necks without any problem, but with my 7mm, I only partially turned them. With my 300 RUM I turned them all the way to the shoulder. They were fully neck sized using an expander ball.

    Tlk I have never used a Lee collet style sizer, but I think if the neck were sized correctly (slightly smaller than the bullet diameter) and you used the correct size pilot reamer, there should not be any slop, even with previously fired brass. Something is not right.

    Also, just because you cant seat the bullet manually, doesn't mean the neck is sized properly. You should mic the inside diameter.

    Hope you get it figured out.


    Also, my technique is not to trim until they have been fired. I do agree with turning unfired brass if you can, but if you get once fired brass, I dont see anything wrong with turning it if you fully size the necks with an expander ball.