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Thread: 6PPC cracked necks

  1. #1
    Join Date
    Jan 2015
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    6PPC cracked necks

    Hi
    I have attached a pic of a case fired in my new 6PPC rifle, out of sixty cases fired, seven have developed cracks at the base of the necks, these cases are on their third firing from new. Chamber is .262 neck and cases are turned to .0085 thickness. Berger Column bullets and 29grains of N133.
    Any ideas anyone?
    Regards
    Chris
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    Last edited by Chris M; 01-12-2015 at 05:57 AM.

  2. #2
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    PPC Brass

    What brand of brass? Are you using a bushing die for neck sizing? Are you neck sizing close to .260? Brass that is not annealed will split much easier than annealed brass.

  3. #3
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    Chris,

    I've never seen this in 20 years of shooting the 6PPC - until last season when one of our (very experienced) shooters got exactly the same problem.

    Could it be a batch of brass we have in the UK - where turnover is relatively low compared to the US?

    Vince (UK)

  4. #4
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    6PPC Cracked cases

    Quote Originally Posted by zimmden View Post
    What brand of brass? Are you using a bushing die for neck sizing? Are you neck sizing close to .260? Brass that is not annealed will split much easier than annealed brass.
    Yes, using a custom bushing die, .002" neck tension. Brass is Lapua in the Gold cardboard box. I'm going to turn some new cases and anneal them before firing.

    Chris

  5. #5
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    Quote Originally Posted by VinceB View Post
    Chris,

    I've never seen this in 20 years of shooting the 6PPC - until last season when one of our (very experienced) shooters got exactly the same problem.

    Could it be a batch of brass we have in the UK - where turnover is relatively low compared to the US?

    Vince (UK)
    Hi Vince
    I was shooting at Bisley on Sunday and neither Phil Sammons nor Steve Newman had seen any thing like it before. Nor could they think of anything I was doing wrong.

    Chris (UK)

  6. #6
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    How far are you bumping the necks back? Shouldn't be more than 0.001

  7. #7
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    Quote Originally Posted by Uthink Uknow View Post
    How far are you bumping the necks back? Shouldn't be more than 0.001
    Hi
    Bumping necks about .0015" but will check again when I resize the last batch shot.

    Chris (UK)

  8. #8
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    Abilene, Texas
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    Quote Originally Posted by Chris M View Post
    Hi
    Bumping necks about .0015" but will check again when I resize the last batch shot.

    Chris (UK)
    Maybe you turned the necks too far into the shoulder.

  9. #9
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    Quote Originally Posted by rcheek View Post
    Maybe you turned the necks too far into the shoulder.
    Thats what it looks like to me.

  10. #10
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    If you section a numerous fired 6PPC made from a 220 Russian Case, you will see a distinct line where the metal flowed from the originol shape of the 220 case to the larger 6PPC neck/shoulder. Regardless of our efforts, it will always seem to form a spot right there that is thinner than the rest of the neck.

    I cured a lot of this by fire forming, and then turning the necks. The two pictures show a case neck turned before fire forming, and on neck turned after.

    This is a .269 neck. Think how then that spot is on a typical .262 neck.

    Annealing might help, if the cases for some reason are a tad brittle out of the box.


    http://benchrest.com/attachment.php?...1&d=1421079496
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  11. #11
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    Case turned after fire forming. You can see the absence of that thin spot.


    http://benchrest.com/attachment.php?...1&d=1421079651
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  12. #12
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    Smile

    Quote Originally Posted by jackie schmidt View Post
    If you section a numerous fired 6PPC made from a 220 Russian Case, you will see a distinct line where the metal flowed from the originol shape of the 220 case to the larger 6PPC neck/shoulder. Regardless of our efforts, it will always seem to form a spot right there that is thinner than the rest of the neck.

    I cured a lot of this by fire forming, and then turning the necks. The two pictures show a case neck turned before fire forming, and on neck turned after.

    This is a .269 neck. Think how then that spot is on a typical .262 neck.

    Annealing might help, if the cases for some reason are a tad brittle out of the box.


    http://benchrest.com/attachment.php?...1&d=1421079496
    Thanks Jackie, I think you've cracked it (Pardon the pun) this is exactly where they have cracked. I've annealed the remaining fired cases and another box of 100 cases bought at the same time.

    Chris

  13. #13
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    Quote Originally Posted by rcheek View Post
    Maybe you turned the necks too far into the shoulder.
    I had a batch of 25 where I did exactly that. Couple of times the neck stayed in the chamber and I couldn't chamber the next round. Happened during a match. Fortunately the necks just dropped out. Lesson learned!

  14. #14
    Join Date
    Oct 2014
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    It looks like it must be related to turning but one other thing to check would be to make sure you didn't load up some bullets with large die rings. I'd mic over some loaded rounds just to make sure you've got some neck clearance.

  15. #15
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    Quote Originally Posted by Carson View Post
    It looks like it must be related to turning but one other thing to check would be to make sure you didn't load up some bullets with large die rings. I'd mic over some loaded rounds just to make sure you've got some neck clearance.
    Thanks for the input

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