crown

Discussion in 'Gunsmithing' started by dud, Mar 3, 2010.

  1. dud

    dud Well-Known Member

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    what kind of crown would you put on a 2506ai,10 twist,27 inch barrel?gun will be mostly used off bench for 100 gr and under bullets under 500 yd shots at groundhogs.does it matter
     
  2. cuutter

    cuutter Well-Known Member

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    I machine the recessed target crown on everything I build. It seems to worh well with all the cal. I build. Hopes this helps.

    Wayne
     

  3. MTBULLET

    MTBULLET Well-Known Member

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    I like the 11 deg. target crown. It's easy to re-do if neccesary, and easy to see if it's damaged. Also very accurate for me.
     
  4. J E Custom

    J E Custom Well-Known Member

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    +1

    I use different crowns for different purposes but mostly the 11 deg.

    I don't find any accuracy advantage in any crown if it is done well, but a
    big dissadvantage if it is not.

    J E CUSTOM
     
  5. dud

    dud Well-Known Member

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    thank you all.my last gun was an 11 degree and works well but wondered if the recessed was better.but i do see where the 11 would be easier to touch up.my smith will be back next week so i am excited to get this project going.
     
  6. NesikaChad

    NesikaChad Well-Known Member

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    Hacksaw. . .:D Use a new blade though. . .
     
  7. topbrass

    topbrass Well-Known Member

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    An 11 degree crown is recessed.
     
  8. MTBULLET

    MTBULLET Well-Known Member

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    the 11 deg. target crown is not recessed, per sey, only the slight depression caused by the 11 deg. shape.
     
  9. topbrass

    topbrass Well-Known Member

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    It is recessed per se. It is just not a stepped down 90 deg. crown. The 11 deg. crown is easier to maintain and affords plenty of protection. Generally it will be as deep as a 90 degree stepped crown, it just doesnt look that way.
     
  10. KNHOTROD

    KNHOTROD Well-Known Member

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    With all the different guns I had built I wanted and love the 11 degree crown concentric to the bore within .0002" with a 60 degree chamfer has worked get on all of my toys.
     
  11. Fitch

    Fitch Well-Known Member

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    One of these:

    [​IMG]

    What is important about the crown is to have the plane of the crown at the muzzle perfectly orthogonal to the bore centerline at the muzzle, and have the edge of the exit hole perfectly symmetrical. For me that is easiest to do with a recessed target crown like this one. Crisp square edge, no bevel is easiest way for me to make sure all is symmetrical.

    The only reason for the recess it to provide some measure of protection from damage. Other than that if it was a perfectly flat crown it would work fine.

    The 11 degree crowns with a crisp edge work as well, they are just harder to make, so I do it this way.

    Fitch

    Fitch
     
  12. topbrass

    topbrass Well-Known Member

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    Do you break the thin edge of the bore to keep it from burning off unevenly?
     
  13. Fitch

    Fitch Well-Known Member

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    No, I don't. I cut it with a very sharp freshly honed HSS tool and oil. I leave it as cut. The edge is square and quite sharp. If the new camera adaptor I made for the borescope yesterday works as well as I hope it does, I'll see if I can post a picture of a this same crown a year, 500 rounds, and a number of cleanings later.

    After a bronze brush has been run over the new crown it burnishes up sharp and square. It will stay that way unless abused.

    Fitch