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Thread: A velocity question for you smart guys

  1. #16
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    I agree that small groups can be shot in short range BR with a large ES, just as long as the velocity swing isn't so wide that you get outside of your tune window. I have personally seen single digit ES with weighed charges from the 6PPC, but it is not common. I believe the 30BR would show smaller ES than the 6PPC. Below is a report from my Labradar. This is typical for the 30-30 with weighed charges. While I don't put greater faith in my lowest ES loads, I believe if anything, it tells you things are working together like consistent ignition. This load was a 118gr bullet with 39.3gr of N133 and a large Wolf primer.

    Michael
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    Last edited by mturner; 07-17-2018 at 01:39 AM.

  2. #17
    Join Date
    Nov 2006
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    ME
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    Do the general comments

    that ES doesn't matter much in short rang br a function of the short range or that some barrels handle certain spreads better than others...in other words go out of tune with a smaller es range?

  3. #18
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    Quote Originally Posted by glp View Post
    that ES doesn't matter much in short rang br a function of the short range or that some barrels handle certain spreads better than others...in other words go out of tune with a smaller es range?
    Greg,

    This mainly has to do with bullet drop. A 6PPC at 100 yards will only see about .05" bullet drop if a bullet that is part of a group is running 40 fps slower. If you look at a 1000 yard rifle shooting a .700 BC bullet at 3000 fps, a bullet that is part of a group will hit about 6.5" below the group if the velocity is down by 40 fps. These are estimates based on ballistic programs.

    Michael

  4. #19
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    Sep 2008
    Location
    Jacksonville,Florida
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    Quote Originally Posted by mturner View Post
    Greg,

    This mainly has to do with bullet drop. A 6PPC at 100 yards will only see about .05" bullet drop if a bullet that is part of a group is running 40 fps slower. If you look at a 1000 yard rifle shooting a .700 BC bullet at 3000 fps, a bullet that is part of a group will hit about 6.5" below the group if the velocity is down by 40 fps. These are estimates based on ballistic programs.

    Michael
    So,that .050" could mean the difference between a mid-one and a two at 100yards and .100" at 200 yards....right? To me,40fps is huge. Just my thoughts......Dan
    Last edited by gpoldblue; 07-20-2018 at 07:09 PM.

  5. #20
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
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    Quote Originally Posted by gpoldblue View Post
    So that .050" could mean the difference between a mid-one and a two at 100yards and .100" at 200 yards....right? To me 40fps is huge. Just my thoughts......Dan
    Well, no, not really.....

    The whole concept of (tuning) a BR rifle is built around the fact that when tuned the rifle self-compensates for the velocity difference.

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