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Thread: 262 or 268 necks for 6mm PPC

  1. #1
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    262 or 268 necks for 6mm PPC

    I would appreciate hearing yourr thoughts on the current thinking about the best neck dia for 6 MM PPC . I know 262 has been the historic preference but I am hearing that 268 is now preferred.
    Please share your thoughts.
    JPM

  2. #2
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    I just had one rebarreled/chambered in .265 neck

  3. #3
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    I had my reamer made with a .268 neck. However I've never won any matches so my opinion isn't worth much. Does make it a lot easier to turn your brass.

  4. #4
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    I swear that I don't think it matters what the neck size is.... Folks have had exceptional barrels either way and so very many not so exceptional barrels...either way.

  5. #5
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    I have been shooting a .269 since the early 2000's. The only reason I shoot a .269 is ease in turning brass.

    As a note, I have shot no neck turn Norma 6PPC in my .269, and it shot reasonably well. The Norma out of the box typically has about 1/2 thousandth wall thickness variation when checking with a ball micrometer. The loaded round has about .003 overall clearance in my chamber.

  6. #6
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    Is anyone still shooting the .274 neck in matches>

    Is anyone still having luck with a no turn neck in competition?

  7. #7
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    Unhappy Ol' Beggs Again

    Quote Originally Posted by marellaj View Post
    I would appreciate hearing your thoughts on the current thinking about the best neck dia for 6 MM PPC . I know 262 has been the historic preference but I am hearing that 268 is now preferred.
    Please share your thoughts.
    JPM

    When the PPC cartridge was introduced in the late sixties and early seventies Palmisano and Pendell used the SAKO 220 Russian case which had much thinner neck walls than the Lapua and Norma cases in use today. Consequently, it was necessary to turn the necks to around .0080 to .0085 in order to completely clean them up which resulted in chamber neck diameters of .2620 and often .2610.

    The serious benchresters and gunsmiths of that day waited sometimes as much as two years for a custom 6PPC reamer from one of the respected gurus and of course, .262 and .261 neck diameters were the standard of the day. Everything rocked along fairly well until Sako quit making the 220 Russian case and introduced the fully formed Sako 6PPC USA cartridge which had a base diameter of .441 instead of the .438 diameter of the original Sako 220 Russian.

    Of course, the 'new' Sako USA case still required neck turning for all those .261 and 262 chambers out there and with all those custom reamers in use by the top BR gunsmiths, trouble soon began. The newer sizing dies of the day being made for the Sako USA case wouldn't even touch the base of the old brass and mismatches between chambers and sizing dies caused lots of headaches for us newcomers. I got into benchrest in late '87 and the supply of original Sako 220 Russian cases was just drying up. Those that had hoarded a good supply of them were asking as much as three and four dollars apiece. Bummer! Finally Lapua, with the help and encouragement of George Kelbly, saved the day and introduced the magnificent Lapua 220 Russian case, which is largely responsible for bringing BR to where it is today.

    Current thinking on what is the best neck diameter today for use with the 6PPC cartridge which dominates short-range group shooting?

    (Answer) Jackie Schmidt pioneered the .269 which I also use. Boyer and Campbell use .268. Huckeba and Conry both shoot the .268. More and more top shooters are going to the larger necks because of the Lapua 220 Russian case whose necks clean up completely at .0120.

    Hope this helps.

    Gene Beggs
    Last edited by Gene Beggs; 11-03-2018 at 05:54 PM.

  8. #8
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    Ol' Beggs again.

    Quote Originally Posted by chriscovell View Post
    Is anyone still having luck with a no turn neck in competition?


    The long-range benchresters often use no-turn chambers in their versions of the 6 BR. No one is more anal than the thousand yard shooters and they are shooting some phenomenal groups with no-turn necks.

    You would play hell convincing most of the short-range group shooters that benchrest accuracy could be obtained without laborious neck turning but I, for one, know it can be done.

    Both the 22 and 6mm Beggs cartridges are available with no-turn chambers of .257 and .274 respectively. Through testing in the tunnel and in actual match conditions, I'll be darned if I can tell a difference. Sure makes case prep simple and easy;

    1. Remove the new case from the box.
    2. Run the neck over the appropriate expander mandrel.
    3. Deburr inside and out with a 'rocket ship.'
    4. Prime, load and shoot!

  9. #9
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    Quote Originally Posted by marellaj View Post
    I would appreciate hearing yourr thoughts on the current thinking about the best neck dia for 6 MM PPC . I know 262 has been the historic preference but I am hearing that 268 is now preferred.
    Please share your thoughts.
    JPM
    I use a .270 neck in competition. I used to use a .263 neck (changed about 5yrs ago) and have found no issues with the .270 when using Lapua brass

    Michael

  10. #10
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    We have some very perceptive folks in this thread....... may I please interject a thought?

    I think the generally accepted reasoning behind close neck clearances stems from two sources, addresses two problems. #1, the close neck match allows neck brass to hold up for a long time because it's not being worked so much and #2 the neck tolerance acts to guide the bullet straight into the rifling. I minimizes "inbore yaw".... And by "close neck tolerance I mean basically anything under 4 thou total clearance, more likely .003 or less.

    If I asked 100 accuracy minded folks, or even 1000 whether or not having .003 total neck clearance on a 6PPC was detrimental to accuracy..... I strongly doubt that even ONE of them would reply "yes, that's TOO MUCH CLEARANCE!"

    "thin to win" and Jack Neary have done a good job of showing that .003 clearance is fine as regards accuracy.

    right??

    NOW...... with 3 thou total clearance that means .0015 per side which in my estimation means that that bullet WILL BE JACKED OVER to one side or another by at least a thou and a half when the bigger hammer shoves it down the bore......

    "no-turn" specs are generally set around .002 over the loaded round neck diameter, maybe .003.

    Now, disregarding the ugly burr on the mouth of new brass can anyone come up with a compelling reason why no-turn necks SHOULDN'T shoot just fine?

    (I happen to have 6BR's in 5 neck sizes, 6PPC's in 4 sizes and 300WSM's in 4 sizes so have some pretty strong opinions on the subject and I'll state right out front that I see NO GAIN in thinner necks FWIW)

    EXCEPT that, when forming very heavy necks....... like 308 from 30-06 cases there can be a set of issues not related to accuracy.

    Them's my thoughts anyway, if anyone cares to comment.

  11. #11
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    Quote Originally Posted by alinwa View Post
    We have some very perceptive folks in this thread....... may I please interject a thought?


    Them's my thoughts anyway, if anyone cares to comment.
    1

    As you know my thoughts ain't even worth 2 cents. Given the fact that a lot of different ways can work really well there must be something in common.
    How much clearance in freebore area for the bullet. Can the firing pin move the case forward any when it hits the primer? Does the case expand fast enough to beat the bullet moving very far?
    Last edited by sdean; 11-04-2018 at 01:05 AM.

  12. #12
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    Quote Originally Posted by Wilbur View Post
    I swear that I don't think it matters what the neck size is.... Folks have had exceptional barrels either way and so very many not so exceptional barrels...either way.

    Wilbur, I agree completely with you on this one. It's just a matter of personal preference. One seems to work as well as another as long as the shooter understands how to manage it. With the ever increasing availability of good, bushing-type sizing dies and chamber reamers one can have about anything he wants including no-turn which is looking better all the time. If there is no difference in accuracy, why put yourself through all that hassle of neck turning?

    Later,

    Gene Beggs

  13. #13
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    Smile Ol' Beggs again.

    Quote Originally Posted by sdean View Post
    1

    As you know my thoughts ain't even worth 2 cents. (sdean, your thoughts are worth as much as anyone's. Thanks for posting. GB

    Given the fact that a lot of different ways can work really well there must be something in common. (Yep, there is. It's called good barrels, bullets, powders, and good loading techniques among others. (GB)

    How much clearance in freebore area for the bullet? I can't speak for all calibers but with the 6 PPC and other 6mm BR cartridges, the diameter of the freebore is usually .2435.

    Can the firing pin move the case forward any when it hits the primer? No; not after the case has been fireformed and assuming the shoulder is not set back excessively during sizing. 9GB)

    Does the case expand fast enough to beat the bullet moving very far? ??, don't know but I wouldn't think it would matter. GB

    Gene Beggs (GB)

  14. #14
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    But,

    The well known centerfire/group benchrest shooter, Tony B, who has 3 times as many HOF points as the second place HOF shooter shoots a 0.263" neck....

    Tell us how your neck diameter is better!!


    ..

  15. #15
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    Angry Here comes ol' Beggs again,

    Quote Originally Posted by JerrySharrett View Post
    The well known centerfire/group benchrest shooter, Tony B, who has 3 times as many HOF points as the second place HOF shooter shoots a 0.263" neck....

    Tell us how your neck diameter is better!!

    ..

    Jerry, I may be mistaken but I thought Tony Boyer shot a .268 neck. Oh well, Tony could shoot just as well with anything. He is a legend the likes of which we will never see again and he's still up there at the cutting edge. Incredible !

    As Wilbur said in his post number four of this thread, "I swear that I don't think it matters what the neck size is."

    Well said Wilbur, I agree.

    Gene Beggs

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