How do gunsmith's determine barrel length?

Discussion in 'Gunsmithing' started by KQguy, Jun 23, 2011.

  1. KQguy

    KQguy Well-Known Member

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    I just had a 7mmWSM built by a gunsmith,I ordered a 27" barrel for it.The barrel measures 25" behind the recoil lug.The barrels exact measurement is 24 15/16".I questioned him about it,and he said he measures from the bolt face to the end of the barrel.Is this how all smith's measure their barrels?I just assumed if I ordered a 27" barrel,I would get 27"(or close to) of actual barrel?
     
  2. edge

    edge Well-Known Member

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    Not a gunsmith but I would measure from the boltface to the crown.

    edge.
     

  3. CHIPLOAD

    CHIPLOAD Member

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    Most blanks come 28+, or 30+ inch any longer usually special order. Turn tennon you loose inch. When crowning you run brushing in and find tight spot cut off there and crown. Some times in a half inch sometimes more. Better to loose 20 fps and have crown where it needs to be. Depending on how your smith indicates his chamber he prob cut some off chamber end too. Maybe he had a bad day and ran his reamer in a little deep and had to bump shoulder and nose cone ahead. Lots of reasons but I'm sure he did his best to get as close to what you wanted as he could.
     
  4. shortgrass

    shortgrass Well-Known Member

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    First, at least an inch is lost on the muzzle end because of lapping. Second, ATF measures barrel length 'from the bolt face to the muzzle'(or end of permanently attached muzzle 'device'). If you wanted a barrel that would finish to 27" that is what you should have asked for, one that would finish to 27". Lately, many are ordering components without knowing what they are ordering.
     
  5. Coyboy

    Coyboy Well-Known Member

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    some barrel makers standard barrel blanks are 27"
    so you ordered a 27" blank, it is common place to cut one inch off the muzzle due to the wash-out from the lapping process.
    As was stated by others all barrels are measured from the breach face to the muzzle.
    You got the longest possible barrel with what you ordered, sounds like it finished at or near 25 3/4"
     
  6. Fitch

    Fitch Well-Known Member

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    Stick a cleaning rod in through the muzzle with the bolt closed. Put a piece of tape around it at the muzzle. Measure from the end of the rod to the tape - that is the barrel length of your rifle, bolt face to crown, as I've always seen it defined.

    If you ordered a 27" barrel, your gunsmith should have included in his cost estimate ordering a blank that would finish to at least 27" as measured above, in other words, 27" bolt face to crown, and delivered a barrel that matched that measurement within practical limits.

    Fitch
     
  7. shortgrass

    shortgrass Well-Known Member

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    Did the customer supply the barrel, or did he have the 'smith order it?