Neck size for 6mmPPC

Discussion in 'Reloading Forum (All Calibers)' started by Joe Marella, Sep 30, 2018.

  1. Joe Marella

    Joe Marella

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    Can anyone provide a brief history of the origins of the 0.262 neck. I am contemplating having a reamer made and I am trying to decide on 0.262 neck or 0.268 neck. My understanding is that the 0.262 is the historic standard but currently the preference is for 0.268.
    JPM
     
  2. liljoe

    liljoe Silver $$ Contributor

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    The 262 neck was from the Sako brass era, it was the neck thickness needed to turn necks for complete cleanup.
    There really is no need for it now with the use of lapua brass. Even using the newer Norma brass the 268 will work.
    Joe
     
  3. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Exactly. Even a .270 would clean up ok but i use a 268- its the most popular these days and way less fragile
     
  4. Tim s

    Tim s

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    I’d like to know where you got those stats because
    I still see far and away more .262-.263’s.
    If not mistaken Jack Neary is still talking comprehensively durring his VV sponsered BR seminars about “cut them thin to win”.
     
  5. Tim s

    Tim s

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    That was never the theory or the purpose. Lets think about this.....do you really think there was ever a case made ever, by anybody, that required a .007”-.008” cut to clean it up.....ever?
     
  6. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    What he means is neck clearance not a thin neck. People used to try to get away with very little clearance around the neck. My stats come from actual experience of putting barrels out there and knowing most of the competitors that shoot on a national level.
     
  7. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Yes there was and yes we had to do it. That was before the time of even vv powder. Had to do it as early as the late 90’s and turning to .0085 still wouldnt clean some up.
     
  8. Tim s

    Tim s

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    Really? I’ listened to two of them with a lot of followup Q&A where he reviews in detail his thoughts including cutting them to .00825”-.0083”, as in “thin”.
     
  9. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Yes and the standard used to be .0087 for a 262nk. Thats what cutting thin to win means. But i doubt jack shoots a 262nk anymore- i havent seen anybody doing that in quite some time. He may have been answering a question to a guy that had a 262nk and he was giving the example
     
  10. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    I was even around in the days where we had to use form dies and make them from 7.62x39 surplus brass. Talk about a sorting and turning nightmare- you could buy 1000 and get 50 if you were lucky. That was when h322 was the powder to win with (not even extreme hogdon).
     
  11. liljoe

    liljoe Silver $$ Contributor

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    I think Jack shoots a 263 neck.
     
  12. Tim s

    Tim s

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    Uhh no Dusty not ever and I’ve been shooting a PPC long enough to have talked to Doc Palmisano about them when I was still shooting a 6X47 when the norm was sleeved guns.
     
  13. Tim s

    Tim s

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    Must not be a top competitor.:)
    He and I must be the last two guys left, well, other than Dwight Scott who supplied my reamer but, sheesh, what does he know, and Tony B of course because that’s why Dwight, I believe, had them done to begin with. That’s a .262”
     
    Last edited: Sep 30, 2018
  14. Tim s

    Tim s

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    No again, that was the whole idea Jack was pushing , far thinner than that.
    Call the guy for yourself rather than misquoting this stuff because there must be 10-15 guys around hete that changed up everything EEXACTLY because of what I told you, including world team participant.
    FWIW, have you ever actually sat in on one of these, because based on how much got misquoted, I’m guseeing not.
     
  15. BoydAllen

    BoydAllen

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    There has been a shift over time by some top shooters to larger loaded round to chamber neck clearances. .003 is not too much. My friend Gary Ocock has a number of records, and he told me that he tries for about 2 3/4 thousandths. Do the math. Carefully measure the pressure ring of the bullet that you favor, subtract that from the chamber neck diameter, subtract your desired clearance, and divide the answer by two. That will be your neck thickness. Fresh cut necks measure about .0001 thicker than they will, clean, after a couple of firings. To get around this I polish them a bit after turning them, under power, while still in the powered case holder, with 0000 steel wool. If I have a bullet that is .2434 at the pressure ring, and the chamber neck is .262, for a clearance slightly under .003 I will cut my necks so that they measure (after 0000 polishing) .0079-.008. This takes into account the fact that chambers will be slightly larger than the reamers that cut them. Jack Neary points out that the advantage of more clearance is most easily visible at 200 yards. Because I find that necks that are this thin are marginal for producing the neck friction that 133 seems to like, my latest chamber has a .263 neck, giving back the neck thickness that I lost going to more clearance, and allowing me to continue to use the same set of neck bushings.
     
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  16. jimmymac

    jimmymac Gold $$ Contributor

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    I've seen the video series. When Neary says cut thin to win, that by default will provide more clearance in the chamber. I think @Tim s and @Dusty Stevens are saying the same thing here. The thinner walls provided more clearance with a given chamber dimension that showed Jack positive results on his targets. At least that is my interpretation of it.

    FWIW, I run a 262 neck and for my chamber, .0082 wall thickness works better for me than the .0085 I started out with.
     
    Last edited: Oct 1, 2018
  17. Tim s

    Tim s

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    That’s the essence of it but I would say in addition, I believe the feeling is also the thinner necks tend to avoid donuts, and assist in consistant levels of workhardening and inconsistant springback.
    I believe the theory is “ less metal, fewer potential variences.
    One of the things that stood out the first time I heard this talk, in particular with guys that tend not to dump cases after asingle match, he said invariably you would end up with at least a couple that would be tighter, seat bullets somewhat harder. Jack stated that if you gave him five rounds, including a tighter one he could absolutely ID it when shot in a group. I’d assume most of this is directed at N133 with higher tension requirements and I still shoot .262’s with .0085” necks but also I’ve been shooting a lot of LT 32 lately and starting to fool with LT30.

    Boyd, you seem to cut them pretty thin. I don’ t know what the exact thinking is now but recall about .0082”-00825” with a .255”-.256” bushing was a pretty good compromise.
     
    Last edited: Oct 1, 2018

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