AR Sponsor
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I'll take a stab at this. I'm sure someone will be along to correct me if I screw it up too badly. The difference in same plane sights versus regular shows up when you flip between sight apertures. If you have an A2 sight handy, look at it. Sight through the small aperture on something, then flip it to the large aperture. Since the hole is bigger, the plane of the rear sight is now lower than the plane of the small aperture. If you were able to take the sight apart and place each aperture side by side you would see a definite step up from one to the other. Why is this important? The difference in the sight planes changes your point of aim. This became quite evident when I first zeroed my AR with A2 sights. When I zeroed with the small aperture then switched to the large aperture my rounds were 3-4 inches lower than the group I had fired with the small aperture. This is why when using the IBZ the sight is adjusted to "bottom out" at 2 clicks below 8/3 or 4 cllicks below 6/3. After they are zeroed with the small hole you turn your sight to 8/3 or 6/3 and flip to the large hole which, since you've raised the rear sight, is now on the same plane as the small hole was when you zeroed. Same plane sights make it so you don't need to adjust the sight depending on which aperture you use. The large and small holes are on the same plane in space and line up with your front sight the same way with no adjustment necessary. Hope this helps. |
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