Parallax Testing

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Who all have tested their optics (especially their "parallax free" red dots) for parallax shifts? Its something we have been looking at in classes recently especially with certain models!
 
What's the best way for us to test this?
There are all sorts of ways depending on your setup, I highly suggest a quick Google or Youtube search. What we did was nestle the rifles down in bags on a bench and get everything nice and snug. Used a 2" bullseye at 100 yards for a same point of a reference. Then shot a centered shot, a high, low, left, and right, and saw how much deviation we got within the shots. Some REALLY surprised us. I can publish the results for anyone interested!
 
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We tested parallax on multiple modern rifle optics- including red dots, holographics, and precision rifle scopes. If you are looking to buy scopes, consider this. Almost all of the red dots were labeled "parallax free" but some failed to meet the claims.

Our method: What we did was put each rifle onto heavy bags, and nestled them down, getting them as level and solid as possible. Used a bullseye for reference and same point of aim at 100 yards. The reason we tested this is we read an article from Green Eye tactical about this same issue (they did a better job than we did). We noticed some students missing on certain shots where angles or rifle cant were an issue (say leaning out behind cover rapidly at 100 yards. We would have them flip up their front iron, see how off center their dot is, center it up, and they'd make the hit. So what we did was fire 1 shot straight on target centered with a front post, then put the dot/reticle to the far left, right, high, and low seeing how that changed the point of impact, then averaged the distance. Keep in mind, very rarely in the real world will you have a perfectly centered dot under stress in a dynamic situation, hence why we want "parallax free." Here are the standard deviations at 100 yards for each (keep in mind most of these are done with basic ARs that group 1.5 inches or so, so any 1.5-2 inch groups with 4 shots can be considered darn close to parallax free.) Some really surprised us:

Trijicon ACOG- 2 inches
Lucid Prism 4x- 1.75 inches
Trijicon MRO (1)- 4.9 inches
Trijicon MRO (2)- 6.3 inches
Aimpoint PRO (1)- 2.1 inches
Aimpoint PRO (2)- 2.3 inches
Aimpoint PRO (3)- 2.9 inches
Vortex SPARC AR (1)- 4.2 inches
Vortex SPARC AR (2)- 4.7 inches
Aimpoint T1- 6.7 inches
Eotech XPS1- 1.45 inches
Eotech XPS3- 2.1 inches
Eotech 516- 1.56 inches
Primary Arms red dot- 5.6 inches
Vortex AMG Razor - 3.5 inches
Burris FastFire- 8.9 inches

You will notice how each brand/model act similar when testing more than one of them. Both Sparc ARs, all 3 eotechs, all 3 PROs, etc all yielded very similar results.

Test 2:
Furthermore- we tested this same test on our 6 inch steel gongs at 100 yards. 5 inches being about the size of vital hit areas for deer or self-defense. The goal was doing the same- one center then one right, left, high, and low in the optic. Keeping them all on the circle was the goal- any more and it was a fail. In our classes- that's enough for you to have the rifle stable and locked down and still miss.

Results- Both MROs, the Primary Arms, the Aimpoint T1, one Sparc AR, and the Burris all failed. The rest, passed. What that told us is our paper tests were spot on. The ones that averaged 4.5 or less passed it and stayed within the steel circle, the ones that did worse all failed.

We took it a step further and did the same paper test with our precision rifles. Keep in mind, these are all capable of 1 inch or less.What we were looking for is parallax shifts in regards to optic and eye offset and with eye relief issues.

Leupold Accupoint 3-9x - 3.4 inches
Leupold Mk4- 3.5-10x- 2.75 inches
Sig Whiskey 3- 2.2 inches
Athlon Midas BTR- 2.1 inches
Athlon Talos BTR- .4 inches
Athlon Neos- .78 inches
Athlon Argos BTR- .73 inches
Night force 5-22- .46 inches
Nikon Black FX1000- .53 inches
Nikon 1-4x- 1.9 inches
Primary Arms ARC2- 1.7 inches
Primary Arms DMR- 4.4 inches

We can see some differences here as well.

Conclusion- Think about coming up on a deer, shooting at an angle off a barricade - or coming up quickly on target without centering perfectly. Consider some of these optics as missing even under stable locked down, cradled in sandbags, on a bench, and think about it in your hands, off axis, and breathing. Don't miss due to some of these optics. Test your own and make your own conclusions. I just wanted to pass on our results. Some of them shocked us and others did way better than we anticipated.

-Ryan
www.apexdefensegroup.com
 
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Sage dynamics on youtube had a couple videos on this that was pretty interesting.

Rds


Magnified optics

So we just posted our results below. Funny, our MROs did terrible compared to most of the others, as did his. I think he hit the nail on the head with the window being larger, but they still can cause a miss even in ideal situations because of it. Interesting! Thanks for posting those!
 
I read a rather unsettling report a while back by Green Eye Tactical which prompted them to ban Aimpoint T1/2s from their Carbine course due to the absolute failure in parallax testing

I have a CompM2 but I haven’t tested the parallax formally.
 
That’s quite a range of optics you tested. I tested a couple of ours with similar results after watching the videos. Although I didn’t measure it was a fair bit of movement with the impacts. Definitely something to think about. Thanks for the info.
 
I read a rather unsettling report a while back by Green Eye Tactical which prompted them to ban Aimpoint T1/2s from their Carbine course due to the absolute failure in parallax testing

I have a CompM2 but I haven’t tested the parallax formally.
Thats it! My T1 did not do well. For sure, it and the MROs did the worst for more "expensive" red dot sights. I was impressed with the Aimpoint Pros.
 
Parallax in a RDS has been a known issue since they came out for service use in 1997.

and I quote:
US Army FM 3-22-9 Marksmanship Manual Chapter 8 section 22
dated 2008

8-22. When operating the M68 CCO, Soldiers no longer need a good stock weld to get a good sight picture after the M68 is zeroed at 25 meters. The M68’s reflexive sight allows the Soldier to fire the weapon with his cheek in a comfortable position, but since the CCO is parallax-free beyond 50 meters only, the Soldier must zero and fire using the same cheek position.

8-31 At ranges of 50 meters and beyond, the effects of parallax are minimal. However, at ranges of 50 meters and closer, parallax exists and the firer must ensure that the red dot is centered while zeroing. 2. The aiming method (two eyes open or one eye open) used to zero must be used to engage targets.

The most simplest way to work out parallax is at 10yds with a boresighting tool.

Great post and topic, most are not even aware this happens.

John
 
So what we did was fire 1 shot straight on target centered with a front post, then put the dot/reticle to the far left, right, high, and low seeing how that changed the point of impact

I'm having a hard time visualizing this test.

Does this mean you fired 5 shots, all with different point of aim? Shooter behind the gun, squared up and taking a shot at the 5 POA.

or....

Did the shooter change his mechanics such that he was seeing the red dot off center in the scope? i.e., not behind the gun, but rather looking through the top/bottom/left/right of the scope's ocular lens?
 
I read a rather unsettling report a while back by Green Eye Tactical which prompted them to ban Aimpoint T1/2s from their Carbine course due to the absolute failure in parallax testing

I have a CompM2 but I haven’t tested the parallax formally.

Honestly, thats a marketing plan to drive traffic.
 
I'm having a hard time visualizing this test.

Does this mean you fired 5 shots, all with different point of aim? Shooter behind the gun, squared up and taking a shot at the 5 POA.

or....

Did the shooter change his mechanics such that he was seeing the red dot off center in the scope? i.e., not behind the gun, but rather looking through the top/bottom/left/right of the scope's ocular lens?

Think about the location of the reticle within the window.

To move the reticle you move your eye, the reticle stays on target, but the way to visualize the reticle has changed. This is how RDS systems work.

To put it the other way, with a normal scope, if you are off center axis you have scope shadow, that shadow moves the shot in the opposite direction.

Under 50yds a RDS does the same thing. But this is a known issue, we first crossed this bridge in 1998... This is why when you shoot a RDS and want to be accurate you must know you mechanical offset AND keep the reticle in the center of the window. After 50yds the location of the reticle in the window is a non-issue.
 
Parallax in a RDS has been a known issue since they came out for service use in 1997.

and I quote:


The most simplest way to work out parallax is at 10yds with a boresighting tool.

Great post and topic, most are not even aware this happens.

John
Correct. I have just seen it more recently with students becoming frustrated with it (specifically the MROs). They will pie the barricade, or get into an awkward position and miss 3-4 shots, I am talking about good 102/201 students which is not normal. I will have them flip their sight post up, center their dot, and boom they make the hit. So some have asked I test a few. We are seeing some changes over 9 inches at 100 yards. All we use are 6 inch gongs and 2/3 size IPSC so that can mean a miss at 100y.
 
Correct. I have just seen it more recently with students becoming frustrated with it (specifically the MROs). They will pie the barricade, or get into an awkward position and miss 3-4 shots, I am talking about good 102/201 students which is not normal. I will have them flip their sight post up, center their dot, and boom they make the hit. So some have asked I test a few. We are seeing some changes over 9 inches at 100 yards. All we use are 6 inch gongs and 2/3 size IPSC so that can mean a miss at 100y.

Hold the phone, 9 inches at 100yds?

PM inbound.
 
Think about the location of the reticle within the window.

To move the reticle you move your eye, the reticle stays on target, but the way to visualize the reticle has changed. This is how RDS systems work.

To put it the other way, with a normal scope, if you are off center axis you have scope shadow, that shadow moves the shot in the opposite direction.

Under 50yds a RDS does the same thing. But this is a known issue, we first crossed this bridge in 1998... This is why when you shoot a RDS and want to be accurate you must know you mechanical offset AND keep the reticle in the center of the window. After 50yds the location of the reticle in the window is a non-issue.

You are spot on up until that last sentence. Manufactures SAY that it is not an issue past 50y, HOWEVER these tests were done at 100y. I have been researching this all day as well after testing ours yesterday. You will find many others testings online yielding very similar results. Some do not show very much change past 50y, while others show significant change past 50y.
 
I'm having a hard time visualizing this test.

Does this mean you fired 5 shots, all with different point of aim? Shooter behind the gun, squared up and taking a shot at the 5 POA.

or....

Did the shooter change his mechanics such that he was seeing the red dot off center in the scope? i.e., not behind the gun, but rather looking through the top/bottom/left/right of the scope's ocular lens?

A combination of both in a way. Shooter stayed square behind the gun, with a proper shoulder weld, mechanics, etc. Only that thing changed was a very slight cheek pressure, with the weapon on bags, shooter square behind the rifle. All shots were fired on at the same POA bullseye. The only thing that changed was holding the dot high, low, right, and left in reference to where it is in the sight, still on the bullseye.
 
A combination of both in a way. Shooter stayed square behind the gun, with a proper shoulder weld, mechanics, etc. Only that thing changed was a very slight cheek pressure, with the weapon on bags, shooter square behind the rifle. All shots were fired on at the same POA bullseye. The only thing that changed was holding the dot high, low, right, and left in reference to where it is in the sight, still on the bullseye.

got it. thanks.
 
Just making sure I understand this ...
In a perfect world, we would always have the dot perfectly centered in the window.
But, in our imperfect world we sometimes have to fire when the dot is near an edge.
So, if we know how much the dot is off from the POI, we can adjust our point of aim.
To avoid paralax, we should always try to be squared and centered if time and circumstances allow.
Did I get that right?
 
Just making sure I understand this ...
In a perfect world, we would always have the dot perfectly centered in the window.
But, in our imperfect world we sometimes have to fire when the dot is near an edge.
So, if we know how much the dot is off from the POI, we can adjust our point of aim.
To avoid paralax, we should always try to be squared and centered if time and circumstances allow.
Did I get that right?
Yes. Ideally, you want to the same sight picture, perfect cheek weld, a centered dot, etc. But in an imperfect world that may not always occur. Derek for instance was bad about canting his rifle when wearing armor and therefore would miss because of his parallax. He runs an MRO and they are known to be bad. 6-9 inches at 100 yards. That's significant on gongs, vitals, or my small little man sized targets. So, if your optic is one that it plagues, just keep that in mind and know your optics limitations
 
Honestly, thats a marketing plan to drive traffic.

The public announcement versus a disclaimer on their course page for equipment requirements may have been a marketing plan, but their testing seems comprehensive enough that their results are hard to argue with.
 
The public announcement versus a disclaimer on their course page for equipment requirements may have been a marketing plan, but their testing seems comprehensive enough that their results are hard to argue with.

Agree,

Since i found this post i have seen some more info and I have to agree that something is up.
 
At the risk of grossly oversimplifying, why can't I just place my rifle in a rest and move my eye around the ocular (left, right, up, and down) to gauge how much parallax there is? If the cross/dot stays reasonably well on target I'm good, at least at that distance. Plus, that's way more deviation in eye placement than one would typically have shot to shot. Anything wrong with this approach?
 
At the risk of grossly oversimplifying, why can't I just place my rifle in a rest and move my eye around the ocular (left, right, up, and down) to gauge how much parallax there is? If the cross/dot stays reasonably well on target I'm good, at least at that distance. Plus, that's way more deviation in eye placement than one would typically have shot to shot. Anything wrong with this approach?

Nope...

Not at all knowing how your gear performs is wise.

Notice the hidden gem in all of this. The front sight. If you get all crazy in the performance of the task, front sight dot cowitness cleans up the garbage.

Oh and understanding magazine high side rule of thumb
 
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At the risk of grossly oversimplifying, why can't I just place my rifle in a rest and move my eye around the ocular (left, right, up, and down) to gauge how much parallax there is? If the cross/dot stays reasonably well on target I'm good, at least at that distance. Plus, that's way more deviation in eye placement than one would typically have shot to shot. Anything wrong with this approach?
True, but I wanted numbers I could actually put down and compare. The old eye test wouldnt give me a true numerical comparison.
 
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