Overbore?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by benzh, Sep 28, 2003.

  1. benzh

    benzh New Member

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    Feb 9, 2003
    Is there a formula that can be used to quantify the degree a catridge is "overbore"?

    Thank you
     
  2. Varmint Hunter

    Varmint Hunter Well-Known Member

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    Here is my formula:

    If the largest safe charge of the slowest practical powder, in a given cartridge, does not fill the case to the bottom of the neck, than it is OVERBORED. [​IMG]
    VH
     
  3. DANTEC

    DANTEC Well-Known Member

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    Jul 6, 2002
    commun formula is V = 1000 d²

    but shape of case can make difference short fat case with sharp shoulder are more efficient ex :

    6 Norma BR compare to 243 WIN
    22 Dasher comapre to 22.250 Rem

    basic idea is when you reach max water capacity for one caliber exemple 70 grain of water in 6.5 cal if you go over your gain in velocity became low compareto the increase of powder volume and if you go to extreme you sometime lose velocity or burn powder for nothing
    exemple :
    7 STW and 7/378 Wea

    so except for fun or fashion better to use a longer barrel than a hudge quantity of powder and avoid by this fact carbon fouling effect wich is very commun with real overbore cartridge

    good shooting

    DAN TEC
     
  4. benzh

    benzh New Member

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    Feb 9, 2003
    DAN TEC

    re commun formula is V = 1000 d²

    Does "V" = Velocity?
    What does "d" represent?

    Also can you give me an example formula for a .308 Winchester load vs. a 300 Ultra Mag? It seems that there should be some logic about the term that can be quantified.
    Thanks
    Howard
     
  5. DANTEC

    DANTEC Well-Known Member

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    v is volume in grain
    d is bullet diamter in inch

    good shooting

    DAN TEC