Need help calculating DOPE......

Discussion in 'Long Range Hunting & Shooting' started by jl3216, Nov 6, 2011.

  1. jl3216

    jl3216 Well-Known Member

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    I have a 300 RUM shooting the 210 Berger VLD at ~3200fps at 3350' AMSL. I have a NXS 5.5-20 MilRad scope zeroed at 200 yards.

    Problem: According to computer software, I need .5 mil for a 300 yard zero and a 1.4mil adjustment for a 475 yard zero. When I dial that dope, I'm about 5" high at 300 and 7" high at 475 yards. Through actual field shooting, the correct DOPE is .1mil for 300 and 1.0 mil for 475yards.

    How do I use the corrected values to create an accurate DOPE chart out to 700 or 800 yards??
    I'm leaving for an elk hunt on Tuesday and would like a more accurate chart (just in case) :)
     
  2. WildRose

    WildRose Well-Known Member

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    Are you sure you are entering your scope height correctly?

    If you are try upping your velocity about 50-100FPS and see how close that puts you.
     
  3. SBruce

    SBruce Well-Known Member

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    Something is definately not right here!!

    If you were hitting dead on at 280-290 and dialed .5mil it would result in being nearly 5" high at 300. You'd also have to be hitting dead on at approx 280-290 for 1.5 mils to give you 7" high at 475. Assuming the input you gave is correct, that's what I get from the my programs.............you can't be zero'd at 200 for this to work out on the ballistic program.

    You're more likely zero'd at 275-300 yds.

    try that zero in your program and then shoot 500, you should be approx 1.2 mils low or 22" low if you dont dial a thing. If that works out, use your program dopes and you should be gtg to 600 without any additional data.

    Are you sure your scope is moving the reticle the true and advertised amounts???

    I've never been a fan of close range zero's, because unless you're shooting a rifle that will print a one hole group at 100 and 200 yds, there's too much room for error in deciding if you're really truly zero'd at precisely those distances. Ballistic programs seem to work much better given the difference in drop between two points, and let that determine your "zero" distance.
     
    Last edited: Nov 7, 2011
  4. WildRose

    WildRose Well-Known Member

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    When you say "zeroed at 200yds"... . Did you actually zero at 200yds, or did you zero at 100yds with your impact high adjusted for a 200yds zero?

    If you did the latter if you are off just a half inch or so it's going to throw the rest into chaos.
     
  5. jl3216

    jl3216 Well-Known Member

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    Thanks for the help guys.

    I'm zereoed at 200 yards, actually shot it. I'll recheck my scope height, but I'm pretty sure it's right . How would I verify the scope is tracking correctly?
     
  6. WildRose

    WildRose Well-Known Member

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    Shoot a box.

    From your centered point go right five clicks and down five clicks. Shoot.

    Go up ten clicks. Shoot.

    Go left Ten clicks. Shoot.

    Go down ten clicks. Shoot.

    Go right five clicks and up five clicks. Shoot.

    You should have a perfect box with a hole in the center.

    You can also do it just going right five. Shoot.

    Left ten. Shoot.

    Right five. Shoot.

    Should be dead centered.

    Up five shoot. Down ten shoot. Up five shoot. Should be dead centered on your final shot.

    You can also then measure the exact distances between shots and see if your clicks are true to what the scope is supposed to be calibrated at. If your clicks are not true then it will throw all your calculations off.
     
  7. jl3216

    jl3216 Well-Known Member

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    I'll review my 200 yards targets again tonight. Maybe I'm just a little high and that would solve my problems.

    Thanks again
     
  8. WildRose

    WildRose Well-Known Member

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    do the box tests at 100yds. That's the easiest to do your calculations on and it saves time.
     
  9. jl3216

    jl3216 Well-Known Member

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    Ok guys, I couldn't stand it. I had my wife get my targets and you were right. I was about .6" high at 200. I had no idea that small amount would cause that large of errors down range! Great lesson to learn at home BEFORE my elk hunt.

    Thanks guys, I really appreciate your help!
     
  10. WildRose

    WildRose Well-Known Member

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    That's not much but plug it into your calculations and see if that accounts for the variance.

    Also measure from center of your rifle bore or bold face (center) to center of your scope tube and see if you are entering that correctly.
     
  11. SBruce

    SBruce Well-Known Member

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    My programs are saying you'd have to be 2.3 to 2.5 inches high at 200 to be dead on at 275. If I use 1.5 sight height or 2.5 sight height, it only makes .2" difference at 200 yds and still zero at 275.?

    I doesn' sound like you were hitting that high at 200, so something is still amiss IMO. Perhaps time to make sure your adjustments are correct with the scope by doing the box test.

    There's a simple way to test the elevation only, and that's to shoot a group with no scope adjustment, then dial up 5 mils and shoot another group. Now back down 5 mils and shoot another shot or two..............the two groups should be 18" apart at 100 yds and the last shot or two should be right in with the original or first group. If your groups are any further apart or closer for that matter, then the scope didn't move exactly 5 mils.

    I am assuming at this point that your scope adjustments are marked in mils and each click is 1/10th mil..??

    Once you've confirmed the adjustments, you can shoot at 300, (without dialing anything), record where you hit.
    Then shoot at 400 without dialing anything, record where you hit. Measure the impact from the aiming point, then dial enough to make that exact change (example, 15" low at 400 equates to just a tad over 1 mil) dial up 1 mil and aim bullseye again. If everything is correct, you should hit the bullseye.

    I would want to know for sure that my dopes and scopes are correct before going after an elk.

    Good Luck
     
    Last edited: Nov 7, 2011
  12. jl3216

    jl3216 Well-Known Member

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    I certainly want everything working right as well when I leave tomorrow. So I'll get busy tonight and hopefully get it all figured out. If not, I'll use another rifle.

    Thanks again for all your help!!!