Speed

Discussion in 'Main Message Board' started by heydogman, Jun 16, 2019.

  1. heydogman

    heydogman

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    .7 grains under Noslers max for 100 BT, 264WM and I get 3644 fps while their max shows 3487. So I check the speed of my .17HMR and it matchs the published speed. Checked my scale. I do have 2 inch's more barrel. Same thing with Barnes data.
     
  2. 243winxb

    243winxb

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    Chronographs should be 15 feet from the muzzle.

    Same barrel length?
     
  3. heydogman

    heydogman

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    Mine's 26 vs their 24.
     
  4. murray brook

    murray brook Silver $$ Contributor

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    What's your pressure like. Any signs..
     
  5. KMart

    KMart Gold $$ Contributor

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    Nosler has been publishing the same data since 2007 in their #6and #7 manual and on the present online data. Your lot of powder could be considerably different than the powder they used or the bullets you have are of slightly smaller diameter than the bullets they tested. Your barrel diameter may be slightly larger than their test barrel.
    Your 2" of barrel gives you about an extra 50 ft of velocity which gives you an extra 107 fps in the end. really close for 12 year old data.
    Find where it shoots accurately and go with that.
     
  6. fyrewall

    fyrewall

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    Allowing for some 30 fps per inch for 2 inches would give 60 fps more MV
    3487 + 60 = 3547
    3547 - 3487 = 60, 60 / 3487 = 1.7 % velocity increase. No big deal, "go with that".
     
  7. heydogman

    heydogman

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    Alright. Was just shocked because I was trying to slow it down with IMR 4350 vs RL22 but it got faster. I don't see any pressure signs. Above the belt is .5135. So far. .
     
    murray brook likes this.
  8. MislMan

    MislMan Silver $$ Contributor

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    Same brand of brass? Volume the same?
     
  9. heydogman

    heydogman

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    Ah. Went from Nosler to Norma. After firing before sizing. Norma 83.8 Nosler 91. Quite a difference.
     
    Dusty Stevens likes this.

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