Effect on POI when occluding red dot sights

[GTF425]

A few posts recently have brought up how phoria will negatively impact POI when shooting with occlused RDS'. Some of the benefits of shooting with a covered RDS include the inability to wash out the dot when using a weapon light or changes in ambient lighting, maintaining a target focus vs dot focus, and allowing the use of an IR light along with an RDS when aiming under NODs (especially useful with pistols).

Molon did testing with a TA11 3.5x ACOG and documented a significant POI shift at 25y. For today, I only had access to a 25y indoor range. With an 11.5" rifle topped with a T2 in LaRue LT660 mount, I fired a quick 10-round group offhand with the RDS uncovered (left target), then closed the solid cover and fired another quick offhand 10rd group (right target). The rifle is zeroed at 200y and POA remained consistent at the center of the B8.



While there is some shift in POI, it is insignificant within CQB distances. I will have access to a 200y range next week and will test on paper and steel at various distances to continue gathering data.

Additionally, I repeated this with a Glock 19 and Holosun HS507c X2. Both were 5 round groups at 25y shooting 124gr Geco 9mm. The top target is with the RDS taped, the bottom is uncovered.



Interestingly, there was no perceptible difference in POI. This could be attributed to the fact that I normally zero my pistols offhand with both eyes open, so I'm already accounting for any effects of phoria.

I'm planning to also test this with a 4x ACOG, 1-6x Razor at 1x/3x/6x, and to stretch the RDS' legs to see how far it can effectively be used while covered.

[markm]

Interesting ideas. If I remember to try this, I can do it on our IPSC sized steel with an Aimpoint at 400 and/or 500 yards next range trip.

[1168]

Great work; thanks.

[GTF425]

I find its utility to be most exploited in CQB-type shooting (home defense being my personal reason). However, I'm assuming you shoot a lot against very bright target backdrops, such as in a desert, and can see this being potentially useful in bright sunlight.

Academic curiosity is the sole reason I'm going to test it at longer distances. I'm curious how the Razor will do across the magnification range...if occluded, it shouldn't make a significant difference between 1x and 6x, but the targets will tell the tale.

[tangolima]

It is a parallax problem, I think. Red dot is supposed to do better. The real holographic sight (eotech?) should have none.

Scope sight, acog included, always has parallax other than the set distance. However it isn't a problem if the shooter's eye is always coaxial to the optics. Phoria makes the eye deviate. The shooter needs to consciously adjust for that. The black ring around the view must be kept even and symmetrical all around.

-TL



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[markm]

I find its utility to be most exploited in CQB-type shooting (home defense being my personal reason). However, I'm assuming you shoot a lot against very bright target backdrops, such as in a desert, and can see this being potentially useful in bright sunlight.

Yes. Agreed. This would be more for the curiosity factor. Stretching out to 400 plus would hopefully show any large POI shifts. I'd really have to get on the gun with the cap closed to see if it would be a fair test... I've never sighted a target that far with the cap shut.

[MegademiC]

A few posts recently have brought up how phoria will negatively impact POI when shooting with occlused RDS'. Some of the benefits of shooting with a covered RDS include the inability to wash out the dot when using a weapon light or changes in ambient lighting, maintaining a target focus vs dot focus, and allowing the use of an IR light along with an RDS when aiming under NODs (especially useful with pistols).

Molon did testing with a TA11 3.5x ACOG and documented a significant POI shift at 25y. For today, I only had access to a 25y indoor range. With an 11.5" rifle topped with a T2 in LaRue LT660 mount, I fired a quick 10-round group offhand with the RDS uncovered (left target), then closed the solid cover and fired another quick offhand 10rd group (right target). The rifle is zeroed at 200y and POA remained consistent at the center of the B8.



While there is some shift in POI, it is insignificant within CQB distances. I will have access to a 200y range next week and will test on paper and steel at various distances to continue gathering data.

Additionally, I repeated this with a Glock 19 and Holosun HS507c X2. Both were 5 round groups at 25y shooting 124gr Geco 9mm. The top target is with the RDS taped, the bottom is uncovered.



Interestingly, there was no perceptible difference in POI. This could be attributed to the fact that I normally zero my pistols offhand with both eyes open, so I'm already accounting for any effects of phoria.

I'm planning to also test this with a 4x ACOG, 1-6x Razor at 1x/3x/6x, and to stretch the RDS' legs to see how far it can effectively be used while covered.

The best way to test this is to look at the target, and only get behind the optic for a quick sight picture.IME the longer you sit occluded the more phoria impacts you.

People do this in uspsa comps while training themselves and still place top 5 or win. I would not do it for precision work (sitting behind the sight), but for reactive- mid or fast paced shooting it should be fine for a/c zone hits to decent distsnce... hell ive hit 8" targets consistently at 60 with no sights on a rifle, occluded would be much better.

[GTF425]

The best way to test this is to look at the target, and only get behind the optic for a quick sight picture.IME the longer you sit occluded the more phoria impacts you.

People do this in uspsa comps while training themselves and still place top 5 or win. I would not do it for precision work (sitting behind the sight), but for reactive- mid or fast paced shooting it should be fine for a/c zone hits to decent distsnce... hell ive hit 8" targets consistently at 60 with no sights on a rifle, occluded would be much better.

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. I'm mostly curious to see how far it can be pushed more than anything. Magnified optics are coming later this week.

[Defaultmp3]

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. I'm mostly curious to see how far it can be pushed more than anything. Magnified optics are coming later this week.

I don't think anyone has said that everyone would be 12" off target at 25 yards if you use an occluded sight, but instead that it is possible for some individuals to be that far off. Some folks can absolutely do good work using occluded sights. Others will struggle. While I applaud your attempts to gather data, they're nothing more than n = 1, and thus don't really say anything outside of the fact that occluded sights work pretty well for an unknown percentage of folks.

[GTF425]

Saves me the hassle of possibly encouraging others to try something new. Carry on with our regularly programmed budget LPVO threads.