Re: Some New Articles At Shooting Voodoo
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LibertyOptics</div><div class="ubbcode-body">Correct me if I'm wrong, but I thought when you dial in elevation (move the bullet impact up) the reticle (and this erector tube) moves DOWNWARD inside the scope tube?? All things being equal, you have to then raise the barrel tip to get the reticle back on target, which helps you "launch" the bullet?
Scott </div></div>
Scott,
although it is counter-intuitive, the erector does really move upwards when adjusting for longer range.
Adjusting elevation on a scope works differently from using a canted (or even adjustable) base to gain adjustment for long ranges. In case ofthe canted base you really <span style="font-style: italic">tilt the whole scope downward</span>, which in turn forces you to raise the barrel to get your crosshairs back on target.
Now when you adjust POI by tilting the erector, things are different. Remember that the objective system creates an upside-down image in the first focal plane. Now when you adjust the reticle (rifle is fixed and not moving!), the image created by the objective system stays exactly the same, and it is located in the same place inside the scope tube, because the objective system is fixed to that very scope tube which is in turn fixed to the stationary rifle. The thing that changes is the portion of the image that the erector system “looks at”. You can think of this as a small circle moving inside a bigger circle, the big circle (FFP image created by objective system) stays the same and always shows the same image, but the small circle (portion of the image that the erector with the reticle looks at) moves inside the larger circle.
Since the FFP image is upside-down (that’s why we need an <span style="font-style: italic">erector</span> system to erect it), moving the erector (mechanically) upwards will point the reticle at a portion of the target that is <span style="font-style: italic">below</span> center, thus force us to raise the muzzle of the rifle to get the reticle back on target.
Another way to put it is that you are not acurally looking <span style="font-style: italic">through the scope at the target at a certain angle</span>, but rather <span style="font-style: italic">at a specific part of the image</span> in the first focal plane.
If I've confused you even more, feel free to stop by at the Premier booth at SHOT and I'll try to do better face-to-face.
