Chamber on .300 WSM

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by tomt, Feb 13, 2011.

  1. tomt

    tomt Well-Known Member

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    Dec 7, 2010
    I just got a new Browning X-Bolt in .300 WSM. I have a number of different .30 cal bullets and was going to update my spreadsheet on the gun. I use the Hornady O.A.L. Gauge with the modified case. When I started checking freebore on different bullets, I noticed I could not even get to the Max OAL of 2.860". My other guns have plenty of freebore to set different OAL. Is this normal for the .300 WSM to have very little freebore?
     
  2. J E Custom

    J E Custom Well-Known Member

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    No it is not normal. the new "High" Pressure cartriges Like the WSMs and RUMs have more
    free bore to allow for higher pressures.

    If yours is short you will have to start loads well off the max loads listed and work up.

    Don't be surprised if you dont get the velocity you want before signs of pressure appear.

    Yours is not the only one that I have heard of like that.

    J E CUSTOM
     

  3. tomt

    tomt Well-Known Member

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    Dec 7, 2010
    Here are two different links to the same article on "3 inch .300 WSM"
    http://www.loaddata.com/articles/PDF/3-Inch%20300%20WSM.pdf

    http://www.riflemagazine.com/magazine/PDF/R_219_preview.pdf

    In the article it gives chamber drawning and if I read it correctly, from the breech face to the riflings is 2.316". Here is my data from the spreadsheet.
    It appears my chamber is out of spec.

    MANUFACTURE C.O.A.L. OGIVE
    Barnes 150 tsx 2.800 2.163
    Barnes 168 tsx 2.770 2.187
    Hornady 178 amax 2.777 2.151
    Sierra 165 GK 2.638 2.176
    Nosler 180 Accu 2.812 2.188

    Should I send it back to Browning to bring the chamber to specs?
     
    Last edited: Feb 13, 2011
  4. elkaholic

    elkaholic Well-Known Member

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    I'm not a gunsmith but that sounds strange. J.E. can probably straighten you out on this but I don't know how they could do that at the factory without using a separate throat reamer?..........Rich