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Need some help extrapolating my drop data.

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  #8  
Unread 03-16-2010, 11:27 PM
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Re: Need some help extrapolating my drop data.

For me, I measure the Objective of the scope and the barrel right under it because I can get the best measurement there. The cant is measured in thousandths and the slight difference you would see would not show up in shooting. Being within a tenth is good enough from what I have seen everyone say.
I didn't qualify my scope by shooting I laid out a grid with a yard stick at 100 yrd, locked my rifle down and dialed the scope up 20 MOA and checked to see where I ended up. Seemed to work and it didn't rely on my shooting skill or reloading skill.
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  •   #9  
    Unread 03-16-2010, 11:35 PM
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    Re: Need some help extrapolating my drop data.

    It is hard with such a short shooting distance. I shoot out at 440 yards, 600 yards, 1000 yards and about 1200 yards.
    When shooting to 1000 yards I can get good validation of my drops but when I go the extra to 1200 yards it shows up sligt errors in my velocity inputs.

    I would say the the problems that you are seeing is a combination of velocity error, parallax and chance, group dispersion.

    Try and shoot over longer distances if you can. It will give you a lot of confidence at the shorter ranges.
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      #10  
    Unread 03-16-2010, 11:37 PM
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    Re: Need some help extrapolating my drop data.

    I will try this whenever I can. I was just saying I'm pretty sure the NF is reliable, so whatever drops I get then should be a pretty accurate representation.

    Ok I will measure using what you stated previously at the objective bell.
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      #11  
    Unread 03-17-2010, 05:54 AM
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    Re: Need some help extrapolating my drop data.

    This kind of stuff is what this web site is all about!

    Plenty of good information here.

    It'll extend my barrel life on the "next" barrel.
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      #12  
    Unread 03-17-2010, 08:56 AM
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    Re: Need some help extrapolating my drop data.

    Nightforce has the reputation of accuracy in there turret adjustments, I would still check it when you get a good chance just so you know without doubt that it is indeed correct.
    Every input will become critical as you extend your range, the sooner you get those numbers nailed down hard, the easier it is to start trusting you ballistics program and it also makes spotting the errors easier.
    One thing I started doing was for my zero shooting one cold bore shot at 100yrds, if the windage was perfect I then measure the elevation, which I usually run about 2 in high and input that into the program. My first shot, on target hits went way up, right or wrong it seems to work for me better than hammering away in frustration by shooting groups.
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      #13  
    Unread 03-17-2010, 10:02 PM
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    Re: Need some help extrapolating my drop data.

    Bigngreen,
    thanks for all the help. I'll make sure to check my click values next time I'm out if I can figure out how to anchor the gun so it doesn't
    move whatsoever.

    I have measured the scope height over bore using the method you descibed. Scope centerline is 1.64" above the bore centerline at the tip of the objective.
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      #14  
    Unread 03-17-2010, 10:40 PM
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    Re: Need some help extrapolating my drop data.

    Quote:
    Originally Posted by oliveralan View Post
    bigngreen,
    thanks for all the help. I'll make sure to check my click values next time i'm out if i can figure out how to anchor the gun so it doesn't
    move whatsoever. clamp it in a cleaning vise then c-clamp the vise to the bench and adjust with shims. Its easier to shot a square though......

    i have measured the scope height over bore using the method you descibed. Scope centerline is 1.64" above the bore centerline at the tip of the objective. this should get you pretty darn close.
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