verifying freebore

Discussion in 'Advanced Gunsmithing & Engineering' started by Jay Christopherson, Jun 27, 2017.

  1. jsthntn247

    jsthntn247 Silver $$ Contributor

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    I know several rifles cut with the same reamer as mine. All of those guys freebore is around .040 shorter than mine. All of our headspace dimensions are the same. Does this mean my barrel diameter is on the large size?
     
  2. Jay Christopherson

    Jay Christopherson it's turtles, all the way down Administrator

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    How was it determined that their freebore is. 040" shorter than yours?
     
  3. jsthntn247

    jsthntn247 Silver $$ Contributor

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    Same bullets, cases, and gauges being used. They are all within a few thou of each other and im 40k longer based off ogive and tip measurements when touching lands. Same reamer looks like you are questioning, 308 Ftr reamer.
     
  4. hogpatrol

    hogpatrol Gold $$ Contributor

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    Are you sure it's. .040 and not .004? What method are you using, the Hornady unit or the stripped bolt & bolt click method?
     
  5. jsthntn247

    jsthntn247 Silver $$ Contributor

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    Nope its .040. I know 2 other people on here that used different FTR reamers and their dimensions match the other guns and mine is about the same length longer. I've done the stripped bolt method, hornady inserts with stoney point, and shining a bullet with steel wool and seating it looking for land marks, mine is allot longer for some reason.
     
  6. savagedasher

    savagedasher Gold $$ Contributor

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    Doesn't free bore change with every shot ? If you use the same method every time you should be able to see the change . The correct method is the one you use .
    Larry
     
  7. hogpatrol

    hogpatrol Gold $$ Contributor

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    Have the other rifles been borescoped? Are their chambers squeaky clean with no carbon ring? I believe something is amiss here in the measuring process.
     
  8. Jay Christopherson

    Jay Christopherson it's turtles, all the way down Administrator

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    Not unless you are capable of measuring freebore to something like .00001" or smaller. No person or method I am aware of is capable of that.
     
  9. savagedasher

    savagedasher Gold $$ Contributor

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    Not or do I care . After it is shot 100 time it will change . Not what it was cut at the wear . Larry
     
  10. Jay Christopherson

    Jay Christopherson it's turtles, all the way down Administrator

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    Care I shot . 100 wear cut but back. Yes!
     
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  11. DaveTooley

    DaveTooley Silver $$ Contributor

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    Same design/spec/name or was the same reamer used on different barrels?.
     
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  12. Alex Wheeler

    Alex Wheeler Gold $$ Contributor

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    I have seen the same reamer end up with different seating depths if used in different brand barrels. Different bore and groove diameters can effect where the bullets ogive touches.
     

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