Crown, accuracy, and BC

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Michael Courtney, Mar 6, 2011.

  1. Michael Courtney

    Michael Courtney Silver Member

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    There's a great article by Alan Marshall in the March 2011 Precision Shooting about the effect of an intentionally damaged crown on accuracy and BC. There's also some solid data on rifle to rifle and shot to shot variations in BC.
     
  2. nitrousmudbogger

    nitrousmudbogger Well-Known Member

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    That was an awesome article! Just makes you want to go dremel the end of your barrel.LOL. The more he wrecked the end of the barrel the better the rifle shot. I would love to try it but my luck might not be so good. So much for all of the hard core guys thinking crown is king
     
  3. CRNA

    CRNA Well-Known Member

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    Do you guys have a link to the article? Thanks.
     
  4. nitrousmudbogger

    nitrousmudbogger Well-Known Member

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    Its in this months Precision shooting magazine. I dont think they have anything online.
     
  5. J E Custom

    J E Custom Well-Known Member

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    This should be some good reading If the members will post on this subject !!!!!!!

    J E CUSTOM
     
  6. nitrousmudbogger

    nitrousmudbogger Well-Known Member

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    Its in this months Precision shooting magazine. I dont think they have anything online.
     
  7. J E Custom

    J E Custom Well-Known Member

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    Come one guys !!

    I can't wait to hear some stories like the guy that sawed off his barrel with a hacksaw and it
    shot better.

    or ????????

    I am trying to find the artical to read and form my own opinion on the results.


    J E CUSTOM
     
  8. Good

    Good Well-Known Member

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    I've always thought as long as the crown remains consistent, the shot will be consistent using consistent ammo. Does it truly matter if someone hacks their barrel off, as long as the load remains consistent, it's escaping the barrel the same way every time right? Maybe after the hack job the bullets impact 3 inches low and right, but consistently... ???
     
  9. J E Custom

    J E Custom Well-Known Member

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    I dont believe the crown is King but it is the last thing that has any effect on the bullet.

    To have an accurate rifle everything is important. Action Trueness, barrel quality, chamber
    quality, load consistency,bedding (Stock to action fit), The crown, and the shooter.

    If one of these things are not correct the rifle will not shoot one hole groups.

    If you are shooting at 100 yards a bad crown may not hurt that much but at distances of 200+
    yards it will begin to have a noticeable effect.

    I have known BR shooters that re-crowned many times to make there rifle shoot.

    I have never seen a fresh crown hurt accuracy just the opposite.

    Believe what you want about the importance of a good crown But don't believe everything you read
    in a magazine.

    J E CUSTOM
     
    Last edited: Mar 8, 2011
  10. anyrange

    anyrange Member

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  11. Good

    Good Well-Known Member

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    Haha, that's good. Nice play on words.
     
  12. LouBoyd

    LouBoyd Well-Known Member

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    The shape and symmetry of the crown is only part of the story of how much a bullet is upset as it passes the crown. The shape and symmetry of the base of the bullet is at least as important, and the muzzle pressure has an important effect. If the muzzle pressure was zero as the bullet passes the crown neither crown symmetry or bullet base symmetry would have the same effect on accuracy relative to having a a few thousand psi of propellant gas blowing on the base of the unsupported bullet. Certainly there are many ways a crown can affect accuracy as can defects at other locations in the barrel. Barrels can damage or distort bullets before they reach the crown. Blowby can also take place in any enlarged portion of the barrel including at the crown. The properties of the bullet and it's ability to seal the bore over the length of the bore matters too.

    Having a perfect crown does not insure accuracy, Bullet base symmetry is more important to group sizes than crown symmetry because the crown symmetry doesn't change angle from shot to shot. Accuracy and precision both come from repeatability.
     
  13. BountyHunter

    BountyHunter Well-Known Member

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    JE

    That is a true story. They guy they were referring to with the hacksaw and RCBS case tool was Boyd Carpenter from Culpepper VA. It was the pistol sillouhette National matches seveal years ago and a referee had in for Boyd as Boyd was a routine winner. The referee claimed he was 1/4" over the barrel length, so Boyd used a hacksaw, cut it off and still won.

    Willie Williamson did the same thing at one of the PA 1K matches, he was an ounce or two overweight and used a hacksaw to cut off a couple inches of barrel. Willie did not win, but shot very good groups still.

    BTW, here is a link to the article. http://www.precisionshooting.com/psm_2011_03_frame.html


    BH
     
    Last edited: Mar 29, 2011
  14. josh3rd

    josh3rd New Member

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    how can one crown his own rifle without the use or availability of a lathe
    lightbulblightbulb