different aim on vertical plane

Discussion in 'Hunter (HFT) & Field Target (FT)' started by pj1967, Oct 28, 2011.

  1. pj1967

    pj1967 New Member

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    can anybody tell me how higher or lower targets affects aim points?
     
  2. Mr P

    Mr P Active Member

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    Anything 30 degree angle + or - approx IE High or low you always aim low as inside the bottom of the kill your impact point will be above the cross hair
     
  3. pj1967

    pj1967 New Member

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    thanx mr. P i will check that out.
     
  4. Delphinus

    Delphinus New Member

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    I don't completely agree, if the target it s close say 10 to 15 yards you must aim the center.
     
  5. Mr P

    Mr P Active Member

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    I guess you did not see the misses on the close reduced kills in Italy this year at the world champioships then
     
  6. villiers

    villiers Self appointed antipimp

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    Last edited: Oct 29, 2011
  7. Gibbs

    Gibbs New Member

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    This is a complicated issue. The pellet is dragged constantly downwards by gravity over time. It's pulled directly vertically downwards over the horizontal distance it travels (not the actual distance it travels)
    So, if your target is 45 degrees up a tree, and the tree is 40 yards away, then your pellet will only drop over 40 yards, and not the longer distance that your actual target is. (therefore, landing higher than expected)
    The complication comes with the different height of your scope, very steep targets (almost vertical) and the close targets being SO close that the pellet doesn't have time to be affected enough to need adjustment.

    The mathmaticians will be on this soon, and I'll get a headache trying to follow them!

    Good luck and all the best.

    Alec.
     
  8. Delphinus

    Delphinus New Member

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    Gibbs you resume it :)
     
  9. Delphinus

    Delphinus New Member

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    Mr. P

    We shoot 15mm killzones as far as 22yards and what I ask you is to place a target in a tree or in a window in the first floor and shoot it from 10 to 15 yards at a angle of about 50 degrees, you will have a suprise.
     
    Last edited: Oct 29, 2011
  10. RobF

    RobF Administrator Staff Member

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    I've got a little level thingy which is a budding project, but it tells you the ratio for the loss... what you do is angle it at the target, read off the ratio, and multiply that by the range. So if it says 0.9 its 90% of the range you should dial in.

    So for very close targets, say 10 yds, that makes them into 9yds, which we all know will mean a miss. For a 50yd target that makes them a 45yd target, which again is a miss. But for a 30 yd target, it means a 27yd range should be dialled, which on that part of the trajectory will probably mean little or no difference.

    So you need to know the angle, the cosine ratio and the range, otherwise you'll be like me in italy and guessing :D
     
  11. Gibbs

    Gibbs New Member

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    And where DO we aim for a near vertical target anyway?:confused:
    Atb,

    Alec.
     
  12. Mr P

    Mr P Active Member

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    I would think that if i aim INSIDE the bottom of the kill at between 10 and 15 yards and the pellet goes straight to my way of thinking the target will fall over because it has landed where i put my crosshair, now by Delphinius,s theory of aiming dead centre and the pellet landing on the crosshair i would guess the same result would occur thus the target falls over now over here in sunny Ilkeston we only get 1 point for knocking a target over we do NOT get extra points for hitting the kill zone dead centre please correct me again as i am a bit simple.
     
  13. Delphinus

    Delphinus New Member

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    Mr P

    It was already explained by others and I have a cosine indicator in my kit and shoot a lot on paper but don't go by me test it, every kit + shooter will produce a different result.

    The theory it's correct but it uses the path of the pellet and we place the scope 2 inches way from the barrel, shim, etc, that cross the path and destroy the theory specially at close ranges.

    Like Rob explained in my kit at 11 yards I have 86 clicks and at 10 yards I have 110, its 24 clicks difference if the angle produces a cosine of 0.9 that will make me to probably miss.

    Apart from the theory if there’s wind or it’s a stander you probably miss if you shoot the border.
     
    Last edited: Oct 29, 2011
  14. blackscale

    blackscale Member

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    Past and 'at' your 'initial zero'...lets say 15yds, your pellet will be above your crosshairs at 30'.

    Any closer and you will be below your cross hairs but not by the amount you would normally give the target.

    IE a 9 yarder for me is normally 11/2 mildots lets say but at 30' it is 1 mildot.

    So a 30 yd target (my zero) at 30' will see me hitting maybe 20-25mm high. (all from memory)

    Don't even try it with a boinger....:D:D...just joking but it is harder.

    XX:D
     
  15. Gilogrt

    Gilogrt Member

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    Not to be pedantic but it must be confusing as you have contradicted yourself there!
    Gravity is a constant of time so if the tree is 40 yards away and the target is 45 degrees up, ie 40 yards up the tree, the target will be 56 and a bit yards from you.
    This means the pellet will have gravity acting upon it for the same amount of time is if it were shot on a horizontal plane.
    Thing that reduces the drop is the extra vertical force that is applied into the equation when shotting off horizontal.
     
  16. Gibbs

    Gibbs New Member

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    There is NO extra vertical force when shooting off horizontal.
    My post is correct. The pellet will drop over 40 yards, not the 56 yards which it actually travels.(thus landing higher than expected)

    All the best and Happy new year,

    Alec.
     
  17. Gilogrt

    Gilogrt Member

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    So if you shoot 90 degrees up from horizontal, ie straight up in the air. If there was no wind what so ever, the pellet would never cover any horizontal distance so would never fall? False!
    You are applying an upward vertical force which will only cease once gravity has increased at a rate of 9.81ms2 at which point the 2 forces are equal and gravity takes over and the projectile will begin to fall under gravity's force.
    (not taking into account drag)

    Here is some good reading.
    http://www.physicsclassroom.com/class/vectors/u3l2b.cfm
     
  18. Gibbs

    Gibbs New Member

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    Obviously the pellet will fall !!
    But there is no EXTRA vertical force when shooting off the horizontal. Gravity is constant and the force behind the pellet is constant regardless of direction.

    The aimpoints/POI for the very steep targets are a tricky subject though. Aggrivated by the different height of scopes above the barrel.

    Atb,

    Alec.
     
  19. TimG

    TimG Member

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    As I understand it in a 90 degree shot up or down, the effect of gravity makes no difference to trajectory.
    Therefore (ignoring wind effects) a shot at 8 yards or 55 yards would have to be taken compensating for scope centre hight only. This will never happen in the real world of course but it gives you a different perspective rather than trying to work it out from a horizontal point of view. :)
     
  20. rich

    rich Active Member

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    What is a 90 degree shot up or down?

    Is that when the barrel axis is vertical, or when the scope axis is vertical? They are not the same.

    There is no position where the pellet appears to stay on the centre of the crosshairs; that would require the crosshairs to be in the barrel. So the pellet will always cross the line of sight. Tilting the gun up from horizontal and nearer the vertical just brings closer that point.

    Always assuming of course that the scope has been set up properly in the first place.:)
     

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