Quote Originally Posted by GTF425 View Post
I'm doing it because there were tenured members claiming that you'll be 12" plus off target at 25y if you use an occluded sight.
I am 100% confident that's not true, but am gathering the necessary target data to support the hypothesis.
It's shooter dependent, and depends on the amount of phoria that person has. So, what your own results will only prove is what's true for you. In the old thread, what people were discussing was the POI change when you switch back and forth from occluding and looking through the same sight. If you zero occluded and use it that way, like an OEG, that will lessen the effect of a phoria if you have one. Note that phoria can change on the same person as the eye gets fatigued.

If you zero looking through the sight, then use it occluded, that's when you'll see a difference, if you have a phoria. If you don't, then you may not see the effect.
I think that a poll would be a good idea, with many people trying the SAME test, then chiming in with their results. Set up a rifle with red dot (this can be done at home) so that it's pointing out a window at a fixed point. Make sure it's in a rest or on a bipod and you don't move it. Look through the red dot, and confirm it's on the target. Flip the lens cover closed so you're using it occluded and see if the dot changes position on that target. If not, great. Your POI using the optic may be the same. If so, then you can see how much you'll be off.

For me, it's at least a foot at 25 yds difference in the dot shift. Note that I am left handed and shoot rifles using my left eye looking through sights or optics. However I am right eye dominant, so when I occlude the sight I'm now using my right eye to look at the target while the left eye sees the dot and superimposes it. So, this may also be a factor why I'm seeing such a big shift.
When I shoot pistol, I use my right eye (both eyes open). For me, the test is always the same - I see a significant difference in the position of the dot, every single time. YMMV.