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Threading a barrel

Discussion in 'Shooting Related Threads' started by austin fatts, Jan 22, 2010.

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  1. austin fatts

    austin fatts TS Member

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    Dec 22, 2007
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    How is a barrel threaded for choke tubes? How is concentricity held between the barrel and choke tube?

    Austin Fatts
     
  2. PerazziBigBore

    PerazziBigBore TS Member

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    Jan 29, 1998
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    First a reamer with the correct pilot is used to ream the hole to the correct size.. then a piloted tap is used to thread the hole..
     
  3. blkcloud

    blkcloud Active Member

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    Nov 22, 2009
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    I always did them in a 4 jaw chuck to make sure everything was true before I did any metal removal..
     
  4. Big Az Al

    Big Az Al Well-Known Member

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    Location:
    near Tucson Trap
    As PerazziBigBore said:

    "First a reamer with the correct pilot is used to ream the hole to the correct size.. then a piloted tap is used to thread the hole.."

    Then I will add......

    Once the reamer is running true, I like to have a mandrel in the chamber that gives me a true center to push against. the centers I have for my tail stock are to small for a 12 ga chamber and when you get an Autoloader barrel theres that extention to worry about anyway!

    I have seen to many off center bores, in some to my taste, mighty high dollar barrels, and as I was taught, "once you have the opening in the middle running true, the outside can be turned true"

    Al Lingham
     
  5. austin fatts

    austin fatts TS Member

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    Dec 22, 2007
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    Is there a problem with the barrel relieving and going out of round with the material removed and the barrel becoming thinner in the area worked on??

    Austin Fatts
     
  6. Unknown1

    Unknown1 Well-Known Member

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    Nov 5, 2009
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    3,408
    There is concentricity between the barrel and the choke IF the original choke is concentric with the bore or IF the bore is centered in the barrel.

    Since in-place chokes are usually swagged into the barrel there is the possibility that the bore of the choke may be parallel with the bore of the barrel but not centered in it.

    The way to ensure that the choke is concentric with the barrel is to cut off the existing choke and begin from there.

    MK
     
  7. hmb

    hmb Well-Known Member

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    Jan 29, 1998
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    9,442
    First shoot the gun at the paterning board so you know what you are dealing with. Then when you are finnished with your machining shoot it again and you will know how you did. HMB
     
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