Why would brass shoulders stop moving forward?

Discussion in 'Reloading Forum (All Calibers)' started by Falfan2017, Mar 26, 2019.

  1. Falfan2017

    Falfan2017

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    Using a dasher with lapua brass in a custom f class chamber. I always measured the shoulders before and after resizing to make sure I was getting the right sizing. After about 8 firings the shoulder quit moving forward. It used to grow to 1.602 or 1.603 using the Harrels shoulder measure tool and I’d bump it back to 1.600. Now the last couple firings it’s stayed at 1.600 and when I resize it stays at 1.600.

    What could cause this? I’m not having any problems chambering the ammo but I’m curious as I haven’t seen that in any of my other chambers. Also I don’t anneal
     
  2. Stickler

    Stickler Silver $$ Contributor

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    Sounds like a case of "work hardening". Have you annealed the cases recently?
     
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  3. SPJ

    SPJ Gold $$ Contributor

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    Probably time to anneal
     
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  4. Bc'z

    Bc'z Gold $$ Contributor

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    Last statement says it all.
    I just went through this.
    Your gonna have to start annealing.
    I use the poor boy method.
    Dark room with a butane torch and a socket on my cordless drill.
    Get case in to point of flame where it meets neck shoulder junction.
    I'm finding spinning them faster 6-7 count in flame, spinning slower 9 to 10 count.
    This should help with consistency in set back and sizing of neck.
    Reloading sure was easier when I only neck sized.

    Edit... You want to remove brass from flame just as it starts to glow, dont get it RED hot you'll ruin your brass for sure.
    I drop my HOT brass into a pie pan and keep moving. I also let them air cool no water.
     
  5. Falfan2017

    Falfan2017

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    I’ve annealed with the blow torch drill method before it just didn’t seem to affect the groups at all so I quit. Also was never confident I was getting the right temperature and for consistent heating between pieces.
     
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  6. Bc'z

    Bc'z Gold $$ Contributor

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    I feel it's better'n nuthin.
    Let me e'splain.
    I have some hornady 6fove brass with undocumented firings some maybe 6 some maybe 10.
    I wasnt getting consistent set back or bullet hold before poor boy annealing.
    After annealing I had consistant .002 set back, cept the 1st piece I pushed back .008.
    Inside necks all measured .262-.2625.
    Measurements dont lie.

    You'll have to be mindful of putting brass in flame at same angle and contact point of flame, spinning at same speed.
    Start with a charged battery on drill.

    Yes an annealing machine would be better, but a fella has to work with what hes got.
     
  7. rwj

    rwj Gold $$ Contributor

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    Is overall case length increasing or also remaining constant?
     
  8. Falfan2017

    Falfan2017

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    That’s staying constant
     
  9. rwj

    rwj Gold $$ Contributor

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    Verify that the end of the case neck is not contacting the end of the chamber counterbore as it would resist the forward motion of the entire case when the round is fired.
     
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  10. Falfan2017

    Falfan2017

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    I don’t think it is. The cases are measuring 1.540 to 1.543 which is well below the trim length
     
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  11. rwj

    rwj Gold $$ Contributor

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    Ok... but easy to check by cleaning a neck end face, coloring it with a Sharpie, chambering, ejecting, then examining the neck face for smearing/loss of color...
     
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  12. SPJ

    SPJ Gold $$ Contributor

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    Are you getting carbon build up
     
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  13. New Gun

    New Gun Gold $$ Contributor

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    Annealing is like an art form and I still work at it. But I found Tempilaq useful to help me learn the techique of temp flow through the brass as color changes. Oh and I have a Bench Source still an art form. Lol
     
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  14. rardoin

    rardoin Silver $$ Contributor

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    If it is still shooting groups that are where you need them to be.....don't change a thing IMO. No absolute need to anneal if you are not splitting necks.
     
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  15. Falfan2017

    Falfan2017

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    No split necks and groups haven’t changed yet. I would like to get 10 more firings on this brass though to get through the barrel so it might not be a bad idea to anneal
     
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  16. varget204

    varget204

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    Get a bottle of 750 degree tempilaq,when put on inside neck it turns color when proper tempature is reached
     
  17. Ledd Slinger

    Ledd Slinger Gold $$ Contributor

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    This is not really a 'problem' as some might think.

    As to the why?...its because of work hardening. If you have custom dies to match your chamber and headspacing is under .003" and neck clearance is the same or less, you shouldn't have anything to worry about. Not enough flexing there to cause cracking on work hardened brass. And as long as the brass still chambers smoothly and neck tension is remaining consistent, I wouldnt even worry about annealing. The 40 deg shoulder with large surface area is what keeps the brass from growing.

    If brass was growing AND work hardening, you may want to be concerned as the neck walls would be getting thinner and could eventually crack. But you stated case length is staying consistent so you should be good to go. Keep loading and sending rounds down range :)
     
    Last edited: Mar 27, 2019
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  18. Falfan2017

    Falfan2017

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    Using the Harrels sizer fit to the chamber so in theory it’s pretty tight tolerances.
     
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  19. Joe R

    Joe R Silver $$ Contributor

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    This sounds like a good problem to have, enjoy it while it last. Sounds like your chamber and sizing die are ideally matched and after 8 firings any "extra brass" in your cases has already been removed through trimming or neck turning.

    If your rifle is shooting well I would keep doing what you're doing. However, keep in mind that with each firing your brass looses elasticity so extraction and neck splitting could start. That would be a sure sign to start annealing. Here's an interesting paper written by Damon Cali, one of the guys that hangs around here.

    Good luck,

    Joe
     

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  20. Sheldon N

    Sheldon N

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    Never thought I'd say this, but it looks like guffey was right.

    The shoulder does not move! :eek:
     
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