GUN Shooting experts: School me please v. shooting at an elevated target

Discussion in 'On Topic' started by Joe_Cool, Apr 5, 2009.

  1. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Let's say I'm shooting at a target at the top of a stand that's located 100 yards away horizontally, and 20 feet tall. How do I account for the height of the target? Assume my rifle is perfectly accurate and perfectly sighted in for 100 yards, and there is no wind.

    My first thought was to aim high, but after thinking about it more, I thought you'd want to aim dead on for the horizontal distance.

    After further pondering, I'm starting to think I'd want to aim dead on, but on the line-of-sight distance (along the hypotenuse of the triangle), which is a bit higher than dead on for the horizontal distance. But that doesn't seem right, either.

    My reasoning is that the bullet will take some number of seconds (n) to reach the target, and in that time, it will drop 1/2*32.2*n²*12 inches below the muzzle line of sight, and that distance is the same regardless of whether you're shooting horizontally or at an elevated angle.

    Like I said, that doesn't feel right. It seems like I should have to take the angle into account.

    Here's my sample scenario:

    [​IMG]

    As you can see, the line of sight distance is only off by 4 feet, which is a negligible correction at 100 yd, but hopefully you get the idea.
     
  2. LancerV

    LancerV Something Happened OT Supporter

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    You do its not a space vacuum
     
  3. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    If it makes it any clearer, imagine that it's 50 yards high instead of 50 feet, so the difference will be 11 yards. Would I aim at the elevated target as if I were aiming at a level target 111 yards away? Or something different?
     
  4. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Thanks for the accurate, yet completely useless answer. :hs:
     
  5. LancerV

    LancerV Something Happened OT Supporter

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  6. LancerV

    LancerV Something Happened OT Supporter

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    Pretty much you need something to give you the angle and cosine or be fucking amazing at math
     
  7. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Great, another answer that contains no useful information at all. I'm not trying to be a dick, it's just that there's seriously nothing there.

    All that site does is restate the two cases I already brought up in the first post (aim for horizontal distance to target, and for line-of-sight distance to target) and say that it's not accurate. Then it goes on to say that I need a data card or a ballistics calculator.

    Totally not what I'm after. I want some general information on how to correct for elevation when taking a shot. That's why I asked for expert shooters. A simple "aim higher because _____" or "aim lower because _____" would be more helpful.
     
  8. Origyns973

    Origyns973 New Member

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  9. Origyns973

    Origyns973 New Member

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    That article should be sufficient enough to answer all of your questions.
     
  10. LancerV

    LancerV Something Happened OT Supporter

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    Did you even read the article :hsugh:
     
  11. GlobeGuy

    GlobeGuy New Member

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    Ask this to a highschooler, I learned this shit in my AP physics class but I forgets nows. :hs:
     
  12. Keesh

    Keesh New Member

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    For the most part, yes. I don't know why everyone has to make it much more complicated.
     
  13. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Yes, I did. How else do you think I was able to summarize it?
     
  14. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Thanks. :o
     
  15. yar1182

    yar1182 New Member

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    My method is not scientific but it gets my lead onto the long range steel targets.

    [​IMG]

    This is not the chart I use but it is fairly close. For my shooting from prone or some sort of barricade support I'm shooting. Every circumstance I've been in in it is under 15 degrees of elevation. So my correction is 1/2" at most. What this means for the distances I shoot with my AR (under 400 yards) I pretty much use my uncorrected balistic charts. I'm shooting 8" steel plates so there is room for error. Now my buddies that shoot the bolt gun sniper matches have to shoot 1" targets out to 200, 2" targets out to 400 and 4" targets out to 600. They spend way more time studying and memorizing charts than I do. I pretty much work all my math into something like this.

    223 75gr 2760fps - At 30 yards and 260 I'm dead nuts.
    I hold low on targets from 100 yards to 200 yards. I hold center of target from 200 - 300, and I hold top of target 300 - 400. Makes it real easy. I honestly worry much more about wind correction than elevation.
     
  16. AustinL911

    AustinL911 Illudium Q-36 Explosive Space Modulator

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    I was always under the impression that if your target is 100yards away, horizontally, that you still aim as if it were 100yards away, regardless of the heigth.

    i.e. if it's 300yd in the air, you would still aim using your 100yd zero.
     
  17. Keesh

    Keesh New Member

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    Maybe I'm misunderstanding you but: a²+b²=c²

    The higher the elevation, the larger the hypotenuse (distance).
     
  18. AustinL911

    AustinL911 Illudium Q-36 Explosive Space Modulator

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    Edit* - I believe this is why snipers use topo maps and GPS to do their math. Both will give the horizontal distance to the target, instead of the line of sight distance (which will always be more on either an incline or decline). Basic, no-frills laser range finders aren't off much use unless you know the angle of incline in which you're shooting, in which case, you'd need to know your trig to figure that out. More advanced laser range finders will do the math for you based on the angle that they're held.

    If you're shooting uphill, or downhill, and you aim for the line of sight distance, you will ALWAYS overshoot.
     
  19. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    So in other words, within 15 degrees, it's close enough, more or less?
     
  20. LancerV

    LancerV Something Happened OT Supporter

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    This
     
  21. Joe_Cool

    Joe_Cool Never trust a woman or a government. Moderator

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    Yeah, that's what I was thinking. Longer flight time means more bullet drop, so you'd hit low.
     
  22. AustinL911

    AustinL911 Illudium Q-36 Explosive Space Modulator

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    Yea, I understand that the hypotenuse is longer, but it doesn't work that way in practice. I can't tell you the exact science behind it, but I believe it's because bullets travel in an arc, and not a straight line (obviously)
     
  23. LancerV

    LancerV Something Happened OT Supporter

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    Yea because bullets dont travel along a straight line
     
  24. yar1182

    yar1182 New Member

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    I'm not really an expert because the type of shooting I do I have never been put in a situation where I had to shoot more than 15 degrees up or down and it just doesn't seem to be an issue at those angles. If I were a sniper in an urban envroment where I was shooting down from a 50 story building or a hunter firing off a ledge into a valley then I'm sure it would be more of a factor because of the great range of angles where you take shots.

    For more shooting ranges I can't think of many circumstances where your going to get more than a 15 degree angle. Again I dope for wind and distance I have not had to dope for elevation.
     
  25. konrad109

    konrad109 New Member

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    The flight time is longer, but if instead of rotating your LOS you rotate the gravity vector, you get your "perceived drop" (in the NEW down direction) will be the sin of whatever angle you fire on, which will be less than your original drop. This kinda makes up for the extra distance traveled.

    [​IMG]
     

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