Apex Defense Group
Well-Known Member
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!
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!What's the best way for us to test this?
Sage dynamics on youtube had a couple videos on this that was pretty interesting.
Rds
Magnified optics
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.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.
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.
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 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.
Test all 4 and see! Then post your results on here!Dang! I have four H1s (and assume they’ll be similar to the T1s). Bummer : (
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?
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.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.
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.
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.
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 limitationsJust 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?
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.
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.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?