338 Lapua brass still not close to Max Headspace

Discussion in 'Reloading' started by kdumph, May 17, 2014.

  1. kdumph

    kdumph Well-Known Member

    Messages:
    76
    Joined:
    Jul 5, 2013
    I'm on my 4th firing of this Lapua brass, FL sizing every time and i'm still a ways away from the max headspace on my rifle (2.749). I'd like these to be just short of that max measurement, but my cases average around (2.716) after FL sizing on my 4th firing. Is this normal, figured I'd be trimming by now? In the name of consistency should I just trim these all to my shortest case?

    Anyone know what the 338LM brass length is new? Could I be losing some major accuracy due to the short brass here?
     
    Last edited: May 17, 2014
  2. RockZ

    RockZ Well-Known Member

    Messages:
    912
    Joined:
    Mar 10, 2006
    It sounds like you are pushing the shoulder back way too much when you full length resize.
    If you don't have a neck sizer...just back off the full length diie until you get the case to headspace
    the way you want.
    After reading your post again it looks like you don't mean headspace but case length.
    I would keep them at saami dimensions for max. Many shooters do trim to the shortest case length to keep them all standard.
     
  3. kdumph

    kdumph Well-Known Member

    Messages:
    76
    Joined:
    Jul 5, 2013
    I'm only pushing the shoulder back .002 if I remember correctly, so barley any at all. I do mean headspace also, I measured the headspace in the rifle and from what I have read unless I misread, you want the case length to be just short of the max headspace in your rifle.
     
  4. Edd

    Edd Well-Known Member

    Messages:
    2,741
    Joined:
    Jan 26, 2011
    You have your terms confused. Those numbers you are quoting appear to be chamber length vs case length. Headspace is a lot shorter than either of those. The maximum Headspace on a 338 Lapua will be about 2.362".
     
  5. kdumph

    kdumph Well-Known Member

    Messages:
    76
    Joined:
    Jul 5, 2013
    You guys are right I was confusing the term. Yes I mean max chamber length!
     
  6. Edd

    Edd Well-Known Member

    Messages:
    2,741
    Joined:
    Jan 26, 2011
    The specs I have for a maximum case length is 2.724" and a minimum chamber length is 2.734".

    If you have measured your chamber at 2.749" and your brass at 2.716", that gives .033" clearance. Typically the minimum clearance is about .010" with an allowed .020" trim added to that. There is nothing you can do to close yours up except keep shooting. I think you are concerned about nothing.
     
  7. Korhil78

    Korhil78 Well-Known Member

    Messages:
    1,931
    Joined:
    Jun 22, 2011
    Read Edd's post wrong so had to edit my post!
     
  8. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,910
    Joined:
    Jul 29, 2004
    There is no reason to bump the shoulder unless you have trouble chambering the brass.

    Fire the brass, and do a neck size only if it is hard to chamber size it only enough to close the bolt.

    This will tell you what your chamber size and make your brass last for a long time.

    There should not be any head space after firing.

    Case overall length should be .020+ less than the chamber length to prevent crimping the brass
    on chambering. If a bullet will not go in the case mouth after firing the case is to long and is being crimped.

    J E CUSTOM