35 Whelen Freebore Diameter

Discussion in 'Gunsmithing' started by Edd, Jul 15, 2018.

  1. Edd

    Edd Well-Known Member

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    Does anyone know a reason why a 35 Whelen needs a freebore diameter that is .002" larger than the bullet diameter?
     
  2. J E Custom

    J E Custom Well-Known Member

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    The free bore is .360 (.003 thousandths larger than the bullet .357)

    https://saami.org/wp-content/uploads/2018/01/Z299-4_ANSI-SAAMI_CFR.pdf#page=13

    Lots of the older cartridges have this amount of freebore diameter because Older bullets were not as precise as they are now so Maybe they wanted to be sure that there was enough clearance.

    Newer cartridges are generally around .001 thousandth. (.0005 per side)

    That may sound like a lot but it is not. Some cartridges have .004 freebore diameters.

    J E CUSTOM
     
    Last edited: Jul 16, 2018
  3. 35 Whelen

    35 Whelen Well-Known Member

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    I have not heard of freebore in the 35 Whelen. All of my 35 Whelens are newer to new guns so that may be why I have not heard of it. I love learning about firearms and the 35 Whelen is one of my favorites.
     
  4. Edd

    Edd Well-Known Member

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    SAAMI specs on a lot of them is half that much, .00025" per side, and on some of them it is less than half that much, .00020" per side.
     
  5. J E Custom

    J E Custom Well-Known Member

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    The freebore will still be there if it is A SAMMI spec. chamber. Even though it is an older cartridge the reamer specifications on new rifles will be SAMMI unless it is a wildcat.

    Your free bore should be .250. That sounds like a lot, but keep in mind that the 35 Whelen, like so many other older cartridges were designed for round nose type bullets for maximum transfer of energy and needed more free bore.

    J E CUSTOM
     
  6. Edd

    Edd Well-Known Member

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    Anyone know why the 35 Whelen has a .349/.357 bore /groove spec instead of a .350/.358?